Photoelectric EffectWilliam F. ColemanThis is a series of simulations of aspects of the photoelectric effect. There is an animation of the experiment with four choices of incident radiation - low and high intensity "red", to represent low energy light and low and high intensity "blue" to represent higher energy light. Electron production is animated and there is an ammeter to simulate current flow. Additional simulations show the effect of light frequency and intensity. There is a link to a spreadsheet that allows students to choose a sample from among five metals. The spreadsheet includes several questions to be answered after working through the materials.

Photochemistry |

Quantum Chemistry |

Enrichment / Review Materials

Prophine and ProtoporphyrinWilliam F. Coleman, Randall J. WildmanThe WebWare molecules this month are from the article "Photochemotherapy: Light-Dependent Therapies in Medicine" by Edward P. Zovinka and Danielle R. Suneri. The first is a simple porphine, illustrating the ubiquitous four-nitrogen macrocycle, while the second is the protoporphyrin found in heme systems.

Medicinal Chemistry |

Photochemistry

Cannon (GCMP)David M. WhisnantH2 and Cl2 cannon: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we observe the reaction of hydrogen and chlorine and explore some related reactions. The reaction involves a radical mechanism initiated by light. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Chemistry in Focus: A Molecular View of Our WorldNivaldo J. TroFinds ChemEd DL resources related to the sections of the General Chemistry textbook, Chemistry in Focus: A Molecular View of Our World, by Nivaldo J. Tro published by Brooks/Cole, 2009.

The World of Chemistry: EssentialsMelvin Joesten, Mary E. Castellion, John L. HoggFinds ChemEd DL resources related to the sections of the General Chemistry textbook, The World of Chemistry: Essentials, by Melvin Joesten, Mary E. Castellion, John L. Hogg published by Brooks/Cole, 2007.

Laboratory Inquiry in Chemistry, 3rd EditionRichard Bauer, James Birk, Doug SawyerFinds ChemEd DL resources related to the sections of the General Chemistry textbook, Laboratory Inquiry in Chemistry, 3rd Edition, by Richard Bauer, James Birk, Doug Sawyer published by Brooks/Cole, 2009.

Textbook-Integrated Guide for Educational Resources (TIGER)The Textbook-Integrated Guide to Educational Resources (TIGER) is ChemEd DL's new way to find useful online resources. Find your textbook in the list and click on the title. This will take you to a table of contents where you can choose the chapter and section that you are currently studying. A list of resources from ChemEd DL will appear. Click on any resource that seems useful.

ChemPRIMEEd Vitz, John W. MooreFinds ChemEd DL resources related to the sections of the General Chemistry textbook ChemPRIME, a wiki
textbook available free from the ChemEd DL, edited by Ed Vitz, John W. Moore and published by the Chem PRIME Project, 2010.

Mol4D: A Web-Based Computational Chemistry Interface for Educational PurposesOliver Stueker, Ingo Brunberg, Gregor Fels, Hens Borkent, Jack van RooijMol4D (Molecules in Four Dimensions) is a web and Chime based molecule editor and computational interface. Visualization and interactivity are the predominant features. Computational results, based on MOPAC, are obtained within seconds and structures presented using the Chime plug in. Orbital information (in VRML format) and the selection of parameters for a linear or grid scan are options.

The Reaction Rolodex; A Web-Based System for Learning Reactions in Organic ChemistryEric MahanThis Web-based system of note cards has been developed to aid students in learning the vast number of reactions encountered in organic chemistry. A thorough knowledge of these reactions is essential for success in first- and second-semester organic chemistry courses. The reactions are organized by functional group and can be chosen from a menu at the left side of the Web page. Once a particular reaction has been selected, the main frame displays the reactant(s) and reagent(s) along with a question mark in place of the product. After considering the reaction as long as needed, the user can click the question mark to reveal the reaction product. Clicking the product will again hide the answer and regenerate the question mark so that the reaction can be practiced again. Selecting other reactions from the menu on the left allows them to be practiced in the same manner.

Reactions

Helen Cecilia DeSilver Abbott MichaelBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Jane Haldimand MarcetBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Samuel MassieBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Maude Lenora MentenBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Mario J. MolinaBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Ryoji NoyoriBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Mary Engle PenningtonBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Agnes PockelsBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Chandrasekhara Venkata RamanBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Sarah RatnerBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Ellen Swallow RichardsBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Norbert RillieuxBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Enrichment / Review Materials |

Minorities in Chemistry

Mary Lura SherrillBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Hideki ShirakawaBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Enrichment / Review Materials |

Minorities in Chemistry

Florence B. SiebertBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Jokichi TakamineBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Koichi TanakaBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Florence Emeline WallBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Isiah M. WarnerBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Elizabeth Amy Kreiser WeisburgerBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Jane Cooke WrightBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Women in Chemistry |

Enrichment / Review Materials

Dorothy Maud WrinchBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Alejandro ZaffaroniBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Rosalyn Sussman YalowBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Ruth Mary Rogan BeneritoBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Katharine Burr BlodgettBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Rachel Littler BodleyBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Marie Sklodowska CurieBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Biomolecules (Netorials)Rachel Bain, Mithra Biekmohamadi, Liana Lamont, Mike Miller, Rebecca Ottosen, John Todd, and David ShawBiomolecules: this is a resource in the collection "Netorials". This set of modules will provide you with a descriptive overview of the four major classes of biomolecules found in all living organisms: carbohydrates, lipids, proteins, and nucleic acids. The Netorials cover selected topics in first-year chemistry including: Chemical Reactions, Stoichiometry, Thermodynamics, Intermolecular Forces, Acids & Bases, Biomolecules, and Electrochemistry.

Chromatography, Paper (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchChromatography, Paper: this is a resource in the collection "ChemPages Laboratory Resources". Paper chromatography is one method for testing the purity of compounds and identifying substances. Paper chromatography is a useful technique because it is relatively quick and requires small quantities of material. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Chromatography

Chromatography, Thin Layer (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchChromatography, Thin Layer: this is a resource in the collection "ChemPages Laboratory Resources". Thin layer chromatography (TLC) is a method for identifying substances and testing the purity of compounds. TLC is a useful technique because it is relatively quick and requires small quantities of material. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Chromatography |

Thin Layer Chromatography |

Laboratory Equipment / Apparatus

Calorimeter, Coffee Cup (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchCalorimeter, Coffee Cup: this is a resource in the collection "ChemPages Laboratory Resources". A coffee cup calorimeter is a useful, simple device that can be used to measure the temperature change that accompanies a reaction. A Styrofoam cup is used because it is a good insulator. The cup will absorb (or supply) negligible amounts of heat during most General Chemistry experiments. Thus, any change in temperature is assumed to be due only to the reaction, and the heat transferred in the reaction may be calculated. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus |

Calorimetry / Thermochemistry

Conductivity Meter (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchConductivity Meter: this is a resource in the collection "ChemPages Laboratory Resources". A conductivity meter is used to measure the conductivities of electrolytic solutions. Electrodes on the device are dipped into a solution, and the solution's electrical conductivity is registered on the display. Electrical conductivity is defined as the transfer of an electric current through a solid or liquid. In electrolytic solutions, the current is carried by ions, as in solutions of salts, acids or bases. Conductivity is inversely proportional to the resistivity of the solution. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Electrochemical Cells(ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchElectrochemical Cells: this is a resource in the collection "ChemPages Laboratory Resources". The cell design described in this module includes two solutions connected by salt bridge (piece of string) and two electrodes (metal strips) connected to a voltmeter. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus |

Electrolytic / Galvanic Cells / Potentials

Eppendorf Pipet (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchEppendorf Pipet or Digital Pipettor: this is a resource in the collection "ChemPages Laboratory Resources". Digital pipettors deliver liquids in volumes from 1 mL to 1µL or less. They are sometimes called "micropipets", "Eppendorf pipets" or simply "Eppendorfs" after one of the more prevalent brands. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Flask, Volumetric (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchFlask, Volumetric: this is a resource in the collection "ChemPages Laboratory Resources". A volumetric flask is used to measure very precisely one specific volume of liquid (100 mL, 250 mL, etc., depending on which flask you use). This flask is used to accurately prepare a solution of known concentration. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Filtration, Gravity (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchFiltration, Gravity: this is a resource in the collection "ChemPages Laboratory Resources". Filtration is a technique used to separate a solid from a liquid. The solid is separated from the liquid phase by passing the mixture over a filtering media. The mixture can be forced through the filter by either gravity or reduced pressure on one side of the filter (by creating a vacuum). It is possible to separate a solid from a liquid by either technique, however there are advantages to each technique. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Filtration, Vacuum (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchFiltration, Vacuum: this is a resource in the collection "ChemPages Laboratory Resources". Filtration is a technique used to separate a solid from a liquid. The solid is separated from the liquid phase by passing the mixture over a filtering media. The mixture can be forced through the filter by either gravity or reduced pressure on one side of the filter (by creating a vacuum). It is possible to separate a solid from a liquid by either technique, however there are advantages to each technique. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Gas Burner (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchGas Burner: this is a resource in the collection "ChemPages Laboratory Resources". A gas burner is used to heat non-flammable objects or solutions. It can be used to heat objects to very high temperatures. Temperatures in the hottest region of the burner exceed 1000°C. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Graduated Cylinder (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchGraduated Cylinder: this is a resource in the collection "ChemPages Laboratory Resources". Graduated cylinders are used to measure the volume of liquid samples and are available in many different sizes. The measurement accuracy of a graduated cylinder is rather poor (may be as much as 10% off) so you must consider the desired accuracy before choosing to use a graduated cylinder. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Hot Plate-Magnetic Stirrer (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchHot Plate/Magnetic Stirrer: this is a resource in the collection "ChemPages Laboratory Resources". The hotplate/magnetic stirrer is a single device that can heat liquids and stir them with a magnetic stir bar. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Melting Points (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchMelting Points: this is a resource in the collection "ChemPages Laboratory Resources". The melting point is a characteristic property of a substance. It can be used for sample identification and purity determination. The melting point is observed by slowly heating a sample and observing the temperature when the sample has changed from a solid to a liquid. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Mixing (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchMixing: this is a resource in the collection "ChemPages Laboratory Resources". Mixing usually produces and maintains a uniform, homgeneous solution. Mixing two solutions often initiates a reaction by bringing substances into contact. Mixing techniques depend on the volume of the solution, the viscosity of the solution, the type of substances to be mixed, and the equipment available. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

pH Meter (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchpH Meter: this is a resource in the collection "ChemPages Laboratory Resources". A pH meter represents the hydrogen ion concentration in pH units. A pH meter consists of a glass electrode and a read out screen. The glass electrode is made of very thin glass that establishes and measures the electrical potential difference between the analyte solution (the solution to be measured) and an internal reference. The electrical potential is then converted into a pH reading for the sample. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

pH Paper (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchpH Paper: this is a resource in the collection "ChemPages Laboratory Resources". The approximate pH of a solution can be determined by placing a drop of the solution on a piece of indicator paper. Two types of pH paper are commonly used: litmus paper and universal (Alkacid) paper. The type of pH paper used is dependent on the type of measurement and degree of accuracy required. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Pipettor, Digital (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchPipettor, Digital: this is a resource in the collection "ChemPages Laboratory Resources". Digital pipettors deliver liquids in volumes from 1 mL to 1µL or less. They are sometimes called "micropipets", "Eppendorf pipets" or simply "Eppendorfs" after one of the more prevalent brands. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Mohr Pipet (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchMohr Pipet: this is a resource in the collection "ChemPages Laboratory Resources". A Mohr Pipet is a graduated pipet that is designd to deliver small portions of a liquid or solution. These portions are determined by recording the difference between the initial and final volume readings. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Pipet, Volumetric (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchPipet, Volumetric: this is a resource in the collection "ChemPages Laboratory Resources". Pipetting involves drawing a liquid into a pipet and allowing liquid to drain from the pipet in a controlled manner. Pipetting is used to quantitatively transfer a liquid from one container to another. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Pouring (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchPouring: this is a resource in the collection "ChemPages Laboratory Resources". Pouring is a way to transfer material from one container to another. Chemical containers have either screw-top lids or glass stoppers. When removing a screw-top lid be sure to set it down on the bench, top side down. Glass stoppers should be held during the transfer of chemicals. Remember to replace the lid after you are done. Careful handling of lids and stoppers will help to prevent contamination. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Scales (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchScales: this is a resource in the collection "ChemPages Laboratory Resources". Correctly reading a scale is a skill that is important to master. The Spectronic 20?, spectroscope, pipet, buret, graduated cylinder, and many other instruments and devices utlilize scales that must be read properly for successful laboratory work. The procedures outlined in this module should be followed for reading any scalar quantity in the laboratory. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Separatory Funnel (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchSeparatory Funnel and Extraction: this is a resource in the collection "ChemPages Laboratory Resources". A separatory funnel is useful for performing extractions. Extraction is one way of purifying a substance. In an extraction, a solute is transferred from one solvent to another. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Spectrophotometer, Scanning UV-Visible (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchSpectrophotometer, Scanning UV/Visible: this is a resource in the collection "ChemPages Laboratory Resources". A scanning ultraviolet/visible (UV/Vis) spectrophotometer operates on the same principles as a Spectronic 20?. They both can be used for qualitative and quantitative analysis. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

UV-Vis Spectroscopy |

Laboratory Equipment / Apparatus

Spectrometer, Spectronic 20 (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchSpectrometer, Spectronic 20?: this is a resource in the collection "ChemPages Laboratory Resources". The Spectronic 20? is used to measure the absorbance (or transmittance) of solutions. A Spectronic 20? is capable of measuring % transmittance and absorbance over the range of 340 to 950 nm (the range 600 to 950 nm requires a special infrared filter and a different lamp). The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

UV-Vis Spectroscopy |

Laboratory Equipment / Apparatus

Spectroscope, Hand-Held (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchSpectroscope, Hand-Held: this is a resource in the collection "ChemPages Laboratory Resources". A hand-held spectroscope contains a diffraction grating that separates electromagnetic radiation into its component wavelengths. The spectroscope can observe either absorption or emission spectra. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Thermometer (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchThermometer: this is a resource in the collection "ChemPages Laboratory Resources". A thermometer is used to measure the temperature of solids, liquids, or gases. A thermometer contains a liquid (usually mercury or an alcohol solution) in a reservoir whose volume is linearly dependent on the temperature (as the temperature increases, the volume increases). The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Connected ChemistryMike StieffConnected Chemistry, a novel learning environment for teaching chemistry, is appropriate for use in both high school and undergraduate chemistry classrooms. Connected Chemistry comprises several molecular simulations designed to enable instructors to teach chemistry using the perspective of emergent phenomena. That is, it allows students to see observed macro-level chemical phenomena, like many other scientific phenomena, as resultant from the interactions of many individual agents on a micro-level. This perspective is especially appropriate to the study of chemistry where the interactions between multitudes of molecules on the atomic level give rise to the macro-level concepts that students study in the classroom. Connected Chemistry comprises molecular simulations embedded in the NetLogo modeling software (1). The collection contains several predesigned simulations of closed chemical systems to teach specific chemistry concepts. Currently, Connected Chemistry contains models for teaching Brønsted Lowry acid base theory, enzyme kinetics, radical polymerization, buffer chemistry, kinetics, chemical equilibrium, and crystallization. Instructors and students can individually tailor the predesigned simulations or generate new simulations as they are needed in the context of a particular lesson, classroom, or department.

Acids / Bases |

Gases |

Kinetics |

Nuclear / Radiochemistry |

pH |

Titration / Volumetric Analysis |

Polymerization |

Equilibrium |

Catalysis

What's in a Name (2)William F. ColemanA set of Web-based flash cards, either ordered or randomized, for reviewing General Chemistry nomenclature.

Nomenclature / Units / Symbols |

Enrichment / Review Materials

Interactive Molecular OrbitalsWilliam F. ColemanThe majority of Introductory Chemistry texts provide students with an adequate introduction to the visual aspects of the molecular orbital model for homonuclear diatomic molecules. The treatment of heteronuclear diatomic and polyatomic molecules is less uniform. Heteronuclear diatomics, when mentioned, are invariably treated as being derived from homonuclear diatomics. While the atomic orbital energy level differences in heteronuclear diatomics is sometimes pictured, the consequences of those differences for the resultant molecular orbitals are rarely discussed. The discussion of polyatomic molecular orbitals in these texts is limited to showing that parallel p-orbitals produce delocalized pi molecular orbitals. The molecules typically mentioned in this context are benzene, nitrate ion and carbonate ion. However, It is rarely pointed out that the six p-orbitals in benzene would form 6 pi molecular orbitals, and that only one of these orbitals would look like the picture in the text.These interactive modules are designed to clarify this subject.

MO Theory

A Window on the Solid StateWilliam R. Robinson, Laura Yindra, J. David Wright, Kevin J. Carlisle, Scott Luchau, Steve Koralesky, Erik Yusko, David PieperA Window on the Solid State helps students understand and instructors present the structural features of solids. Parts I and II were published previously by JCE Software (1) and Macintosh versions of Parts I and II are also available (2). Parts I and II have been updated to include improvements in art and minor changes in logic. Parts III and IV expand the collection to include the structures of simple ionic solids using the visual effects available in an interactive computer medium. The package provides a tour of the structures commonly used to introduce features of the solid state.

Some Unusual Applications of the "Error-bar" Feature in Excel SpreadsheetsKieran F. LimNovel uses of the "error-bar" feature of spreadsheet packages in the areas of enzyme kinetics, vibrational spectroscopy, vibronic spectroscopy, and mass spectrometry are discussed. It is argued that using software features for purposes that were not envisioned by the programmers fosters flexibility and innovation.

Chemometrics |

Spectroscopy |

Enrichment / Review Materials

Generating a TrendlineWilliam F. ColemanGenerating a Trendline is a visual tutorial showing how to generate a trendline (Excelese for regressions) using Microsoft Excel. The VCR-style controls at the top of the screen may be used to step through the tutorial.

Mathematics / Symbolic Mathematics |

Enrichment / Review Materials

Generating a HistogramWilliam F. ColemanGenerating a Histogram is a visual tutorial showing how to generate a histogram using Micosoft Excel. The VCR-style controls at the top of the screen may be used to step through the tutorial.

Mathematics / Symbolic Mathematics |

Enrichment / Review Materials

The van der Waals Equation of State and the Law of Corresponding States; A Spreadsheet ExperimentP. Venema, H. M. SchainkIn typical physical chemistry courses the student is told how the van der Waals equation works. The mathematics needed for making a Maxwell construction is difficult for the average chemistry student (what is needed are the roots of a cubic polynomial). This makes it difficult to show how the liquid?gas phase diagram is obtained from the equation of state. Here a spreadsheet experiment is presented that can be used to illustrate various aspects of the van der Waals equation of state.

Restricted Hartree-Fock SCF Calculations Using Microsoft ExcelMark A. Freitag, Cortney A. Boots, Taylor R. PageCourses in computational chemistry are increasingly common at the undergraduate level. Excellent user-friendly programs, which make the execution of ab initio calculations quite simple, are available. However, there is a danger that the underlying SCF procedure (usually coupled with contracted Gaussian atomic orbital basis sets) can become a ?black box? for the student. This Microsoft Excel spreadsheet contains all the essential elements of far more complicated ab initio calculations, but on the simplest possible molecular system.

Computational Chemistry |

Mathematics / Symbolic Mathematics |

MO Theory |

Quantum Chemistry |

Theoretical Chemistry

Kinetica; An Excel program to Stimulate or Analyze Kinetic DataLeonel Vera, Pedro Ortega, Miguel GuzmánThe Excel spreadsheet Kinetica both simulates and analyzes kinetic data for simple rate equations of the form: - d[A]/dt = k [A]^n Instructors or students can generate simulated kinetic data using parameters they specify, or using parameters randomized by Kinetica. The data set that is generated may then be exported for use in exercises, homework, and exams, or may be analyzed directly within Kinetica. A kinetics data set may also be imported from an external source into Kinetica for analysis.

Kinetics

Copoly; A Tool for Understanding Copolymerization and Monomer Sequence Distribution of CopolymersMassoud Miri, Juan A. Morales-TiradoThe study of the composition and monomer sequence distribution of binary copolymers is often complicated because of the many definitions of representative properties for the sequence distribution, the numerous calculations required, and occasionally the abstract treatment of the statistical processes describing the copolymer formation. Copoly resolves these issues with a user-friendly, highly visual interface to perform all calculations. Using Microsoft Excel and Word, Copoly is compatible with Windows and Mac OS. In Copoly the students enter up to five independent data parameters using the Data Input Window, and immediately see the results. To obtain diagrams for a copolymerization obeying a second-order Markovian process, the fraction of one monomer, A, and the reactivity ratios, rA, rB, rA´ and rB´ need to be entered; for a first-order Markovian process only the first three of these are required. For a Bernoullian- or zeroth-order Markovian process only A and rA are required. The results are displayed on separate sheets labeled: 1. Copolymerization Diagrams, 2. Dyads and Triads, 3. Sequence Length Distribution, 4. Simulated Copolymer Design, and 5. Summary.

Polymerization

Web-Based Interactive Animation of Organic ReactionsIngo Brunberg, Gregor Fels, Hens Borkent, Jack van Rooij, Oliver StuekeThis WWW-based service for the automated animation of organic reactions we believe to be a versatile tool for teaching and learning organic chemistry. It allows the investigation of the influence of substituents of starting materials on the reaction coordinate and the energy of the depicted reaction. Starting from a list of precalculated organic reactions hydrogen atoms can be substituted by a variety of organic substituents and functional groups using the molecule editor. The new set of starting material is submitted to the calculation of intrinsic reaction coordinates that yields automatically an animation of the reaction that can be viewed with the Chime plugin.

Computational Chemistry |

Molecular Modeling |

Molecular Mechanics / Dynamics |

Enrichment / Review Materials

An Excel Program to Study First-Order KineticsKen MuranakaUser data can be analyzed to determine what parameter values of the first order rate expression give the closest fit, or data can be generated using user-input values of the rate parameters and random noise levels. Statistical characterizations such as confidence limits and variance are calculated.

Kinetics

The Balmer SeriesThis animation briefly introduces the basics of the emission spectra of one-electron atoms and ions. The first four lines of the Balmer series can be highlighted and the wavelengths read. There is a link to an Excel spreadsheet, Bohr1.xls, that explores these spectra in more detail.

Atomic Spectroscopy |

Enrichment / Review Materials

Simple HTML Templates for Creating Science Oriented Jeopardy! Games for Active LearningJoseph J. Grabowski, Michelle L. PriceTo enable more faculty to use another component of active learning in their multimedia-equipped classrooms, we have developed a comprehensive Sciences Jeopardy! Games Web site. Jeopardy! is a unique way to help students master the content of their local course (1). For faculty, Jeopardy! is an engaging, alternative exercise that can enliven lectures or recitations. Our freely accessible Web site offers a number of complete Jeopardy! games for organic chemistry, general chemistry, and biochemistry (both in Web-accessible or zipped, downloadable formats).

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Enrichment / Review Materials

3D NormalModes Shockwave; A Web Application for Interactive Visualization and Three Dimensional PercNickolas D. Charistos, C. A. Tsipis, Michael P. Sigalas3D Normal Modes is a Web application for interactive visualization and three-dimensional perception of the normal modes of molecular vibration, suitable for undergraduate students in chemistry. The application uses the Macromedia Shockwave plug-in and has been designed and developed especially for the Web. It has a simple graphical user interface and requires a download of only 120 KB, allowing it to be used even with low bandwidth Internet connections. Its performance is comparable to a desktop application.

IR Spectroscopy |

Raman Spectroscopy

JavaScript Programs To Calculate Thermodynamic Properties Using Cubic Equations of StatePatrick J. BarrieCubic equations of state are widely used by chemists and chemical engineers to predict the thermodynamic properties of both pure substances and mixtures. In particular, these equations enable predictions concerning the temperature and pressure at which vapor liquid equilibrium occurs. These two educational JavaScript programs perform calculations using cubic equations of state and, equally importantly, explain how the calculations are performed.

Mathematics / Symbolic Mathematics |

Chemometrics |

Thermodynamics |

Equilibrium |

Enrichment / Review Materials

3D Molecular Symmetry Shockwave; A Web Application for Interactive VisualizationNickolas D. Charistos, Constantinos A. Tsipis, Michail P. Sigalas3D Molecular Symmetry Shockwave is a Web-based application for interactive visualization and three-dimensional perception of molecular symmetry. The user interface is simple, and students learn how to use the program from the built-in help screens. The animation uses the Macromedia Shockwave browser plug-in, and requires a download of only 256 KB, allowing it to be used even with low bandwidth Internet connections. Its performance is comparable to a desktop application.

Crystals / Crystallography |

Group Theory / Symmetry |

Molecular Properties / Structure |

Thermodynamics

Interactive SpreadsheetsWilliam F. ColemanInteractive Excel spreadsheets display hard-to-understand concepts in statistics, quantum mechanics, physics, and more. Parameters are adjusted by clicking on easy-to-use buttons or by using numeric input boxes. Graphs, tables, and/or figures are then created reflecting the change in parameters.

Acids / Bases |

Crystal Field / Ligand Field Theory |

Group Theory / Symmetry |

Quantum Chemistry |

Statistical Mechanics |

Titration / Volumetric Analysis |

Coordination Compounds |

Enrichment / Review Materials

An Online Tutorial for Learning Symmetry and Point GroupsWilliam S. Harwood, Ali KorkmazThis free web-based tutorial provides the student with explanations and examples of symmetry elements and makes extensive use of interactive Java applets and flash animation to guide students in seeing the symmetry elements in real molecules. The Java applets provide images generated from crystallographic databases that can be rotated freely in real time. This interactive feature allows students to explore the symmetry of selected molecules and also to test their own understanding. Mouse-over and other flash animations also provide students with a guided means to interpret symmetry elements and how they are depicted. Each symmetry element is discussed in turn with examples and short self-tests that provide immediate feedback to the student.

Quantum States of Atoms and MoleculesTheresa Julia Zielinski, Erica Harvey, Robert Sweeney, David M. HansonQuantum States of Atoms and Molecules is an introduction to quantum mechanics as it relates to spectroscopy, the electronic structure of atoms and molecules, and molecular properties. A digital, living textbook, it provides opportunities not found in conventional textbooks opportunities that allow students to develop skills in information processing, critical thinking or analytical reasoning, and problem solving that are so important for success.

Quantum Chemistry

Acids (GCMP)David M. WhisnantAcids: this is a resource in the collection "General Chemistry Multimedia Problems". We will observe the reaction of sodium bicarbonate with three acid solutions. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Acids and Salts (GCMP)David M. WhisnantAcids and Salts: this is a resource in the collection "General Chemistry Multimedia Problems". This problem will explore a few properties of common acids and their salts. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Acids / Bases

Ammonia (GCMP)David M. WhisnantAmmonia fountain: this is a resource in the collection "General Chemistry Multimedia Problems". In an ammonia fountain, a flask is filled with ammonia gas. A tube from the flask extends into a pan of water that contains phenolphthalein. When a rubber bulb full of water is squeezed, the water squirts into the flask. Water from the pan then is pushed into the flask and the indicator changes color. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Acids / Bases |

Aqueous Solution Chemistry

Burning Magnesium (GCMP)David M. WhisnantBurning Magnesium: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will look at the reactions of two elements with oxygen in air. We will begin by observing the reaction of magnesium metal with oxygen when the metal is heated in air. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Metals

Chromate-Dichromate (GCMP)David M. WhisnantChromate/Dichromate: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will study shifts in the equilibrium between chromate and dichromate. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Oxidation / Reduction

Disorder (GCMP)David M. WhisnantDisorder: this is a resource in the collection "General Chemistry Multimedia Problems". A spontaneous change is one that has a natural tendency to occur without needing to be driven by an external influence. This problem will explore the influence of entropy, a measure of disorder, on the spontaneity of a few processes. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Thermodynamics

Drinking Bird (GCMP)David M. WhisnantDrinking Bird: this is a resource in the collection "General Chemistry Multimedia Problems". The drinking bird's felt-covered head dips into the beaker of water as it bobs up and down. The tube goes from the bottom of the body to its head. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Water / Water Chemistry

Electrolisis 1 (GCMP)David M. WhisnantElectrolisis of Water #1: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will contrast the electrolysis of water with boiling. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Electrochemistry |

Water / Water Chemistry

Electrolisis 2 (GCMP)David M. WhisnantElectrolisis of Water #2: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will contrast the electrolysis of water with boiling. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Electrochemistry |

Water / Water Chemistry

Electrolisis 3 (GCMP)David M. WhisnantElectrolisis of Water #3: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will contrast the electrolysis of water with boiling. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Electrochemistry |

Water / Water Chemistry

Fireworks (GCMP)David M. WhisnantFireworks: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will study the colors produced by metal salts in flames. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Metals

Floating Squares (GCMP)David M. WhisnantFloating Squares: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will coat a piece of notecard with graphite (from pencil lead). We then will float the piece in two beakers containing water and a second solvent. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Physical Properties

Halogens and Halides (GCMP)David M. WhisnantHalogens and Halides: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will study the oxidation-reduction reactions between the halogens and the halide ions. The halogens and halides will be dissolved in water and hexane. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Oxidation / Reduction

Hexane 1 (GCMP)David M. WhisnantHexane 1: this is a resource in the collection "General Chemistry Multimedia Problems". Hexane, a liquid hydrocarbon with the formula C6H14, burns when ignited in the presence of oxygen. In this problem we will observe videos of this combustion reaction. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Alkanes / Cycloalkanes

Hexane 2 (GCMP)David M. WhisnantHexane 2: this is a resource in the collection "General Chemistry Multimedia Problems". Hexane, a liquid hydrocarbon with the formula C6H14, burns when ignited in the presence of oxygen. In this problem we will observe videos of this combustion reaction. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Alkanes / Cycloalkanes

Metals 1 (GCMP)David M. WhisnantReactions of Metals 1: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will observe the reactions of different metals (Zn, Ni, Mn, Fe) with iodine. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Metals

Metals 2 (GCMP)David M. WhisnantReactions of Metals 2: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will observe the reactions of different metals (Zn, Ni, Mn, Fe) with iodine. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Metals

Nitrogen Oxides (GCMP)David M. WhisnantNitrogen Oxides: this is a resource in the collection "General Chemistry Multimedia Problems". Two of the most important nitrogen oxides, N2O4 and NO2, are in equilibrium with each other. We are interested in how this equilibrium shifts with temperature. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Equilibrium

NO and O2 (GCMP)David M. WhisnantNO and O2: this is a resource in the collection "General Chemistry Multimedia Problems". NO and O2 and the product of the corresponding reaction are three gases which have different solubilities in water. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

NO and O2 #2 (GCMP)David M. WhisnantNO and O2 #2: this is a resource in the collection "General Chemistry Multimedia Problems". NO and O2 and the product of the corresponding reaction are three gases which have different solubilities in water. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

NO and O2 #3 (GCMP)David M. WhisnantNO and O2 #3: this is a resource in the collection "General Chemistry Multimedia Problems". NO and O2 and the product of the corresponding reaction are three gases which have different solubilities in water. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Oxides (GCMP)David M. WhisnantOxides: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will explore the properties of the oxides of a few elements. We will add samples of the oxides to universal indicator solution and learn about the acid-base character of the oxides. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Acids / Bases

Paramagnetism (GCMP)David M. WhisnantParamagnetism: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will begin by observing the magnetism of three manganese compounds. These compounds have been placed in capsules, which will be pulled toward a magnet if the compound is paramagnetic. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Magnetic Properties

Phlogiston (GCMP)David M. WhisnantPhlogiston: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will think back to the last half of the 18th century when modern chemistry was beginning to take place. One of the major problems occupying chemists at the time was combustion. The dominant theory of combustion in the mid-18th century involved a substance called "phlogiston." General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Applications of Chemistry

Steam (GCMP)David M. WhisnantSteam: this is a resource in the collection "General Chemistry Multimedia Problems". We observe two videos of steam produced by boiling water. The steam is channeled through a copper coil which will be heated. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Water / Water Chemistry |

Phases / Phase Transitions / Diagrams

Strong Acids (GCMP)David M. WhisnantStrong Acids: this is a resource in the collection "General Chemistry Multimedia Problems". This problem will explore the properties of common strong acids. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Acids / Bases

Two Balloons (GCMP)David M. WhisnantTwo Balloons: this is a resource in the collection "General Chemistry Multimedia Problems". In the Two Balloons video, the left flask contains some water and the right flask contains only air. What do you see when balloons are fastened to the mouths of the hot flasks? General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Gases

Two Solids (GCMP)David M. WhisnantTwo Solids: this is a resource in the collection "General Chemistry Multimedia Problems". When two solids barium hydroxide octahydrate, Ba(OH)2. 8H2O and ammonium thiocyanate, NH4SCN are mixed, they react. We will explore the thermodynamics of the reaction. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Thermodynamics

Water #1 (GCMP)David M. WhisnantWater #1: this is a resource in the collection "General Chemistry Multimedia Problems". Isotopes are forms of the same element composed of atoms that have different numbers of neutrons. In this problem we will begin by observing the properties of water containing two isotopes of hydrogen. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Water / Water Chemistry

Water #2 (GCMP)David M. WhisnantWater #2: this is a resource in the collection "General Chemistry Multimedia Problems". Isotopes are forms of the same element composed of atoms that have different numbers of neutrons. In this problem we will begin by observing the properties of water containing two isotopes of hydrogen. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Water / Water Chemistry

EquilibriumMatthew Sandberg, Mike BellamyUsing a visual approach, this applet is designed to help students learn to solve equilibrium calculations and also to help them gain a deeper understanding of the topic. It can be used by the instructor in the classroom as equilibrium topics are introduced. Sample exercises for students are included. The text is available in both English and Spanish.

Chemometrics |

Equilibrium |

Enrichment / Review Materials

Principal Species and pHRobert M. HansonCalculates concentrations of principal species in solutions using JavaScript. You can specify whether "1st-year" methods or mass-charge balance methods are used in the calculations. Solutions can be chosen from the included set or you can design your own.

Acids / Bases |

Titration / Volumetric Analysis |

pH |

Solutions / Solvents

Hückel Determinant SolverRobert M. HansonGenerates energy diagrams for simple Hückel molecular orbital systems using JavaScript. You can specify the determinant or select one for a specific compound from a list.

Computational Chemistry |

MO Theory |

Theoretical Chemistry |

Enrichment / Review Materials

Mechanism-Based Kinetics SimulatorRobert M. HansonSimulate the kinetics of a reaction based on its mechanism using JavaScript. The idea is to write a mechanism and, based on that, follow the course of concentrations or rates of change in concentration of reactants, catalysts, intermediates, and products over time.

Kinetics |

Catalysis |

Mechanisms of Reactions

The Chemical Name GameRobert M. HansonProvides practice in learning about names and properties of chemical species. You can play this game by yourself or as a group with a moderator to work the mouse and check answers.

Nomenclature / Units / Symbols

What's in a NameRobert M. HansonFocuses on the reasons for learning the names of compounds and ions that by learning the names we are learning information that is immediately helpful in identifying what is going on in an aqueous solution.

Atomic SpectraWilliam F. ColemanIn this Flash animation the user can view the atomic emission spectra (400-700nm) of eight different elements. A dragable marker allows the user to approximate the wavelength of the various spectral lines. The effect of resolution can be examined in the sodium spectrum in the region 550-600nm.

Atomic Spectroscopy |

Quantum Chemistry |

Enrichment / Review Materials

Bohr Hydrogen Atom Emission SeriesWilliam F. ColemanIn this Excel spreadsheet students use interactive arrows to explore various series in the hydrogen spectrum. The arrows change the final quantum state of the series. A second tab opens a sheet that allows exploration of the spectra of other one-electron species, by varying the nuclear charge. The nuclear charge is entered and the arrows again control the final state of the spectral series.

Atomic Spectroscopy |

Quantum Chemistry |

Enrichment / Review Materials

Close Packing of Layers of SpheresWilliam F. ColemanAn animation of the close packing of layers of spheres. In this version, clicking on text links adds the second and third layers, with two options for the third layer. After both ways of adding the third layer have been explored the user has an option to go to a second version that has no text but rather allows the user to drag the layers over one another.

Crystals / Crystallography |

Molecular Properties / Structure |

Solids |

Enrichment / Review Materials

Gold LayersWilliam F. ColemanFour spheres surrounding a tetrahedral hole and six spheres surrounding an octahedral hole are highlighted and are partially transparent to show the holes.

Crystals / Crystallography |

Metals |

Solids |

Enrichment / Review Materials

Lattice EnergyWilliam F. ColemanPowerPoint presentation covering various aspects of the concept of lattice energy at the introductory and intermediate inorganic chemistry level. The presentation will open directly in the browser if your system has been so configured.

Crystals / Crystallography |

Ionic Bonding |

Solids |

Enrichment / Review Materials

QuadraticWilliam F. ColemanShows how the roots of a quadratic change as the b term in the equation changes. The equation was chosen to illustrate the fact that only real roots are seen as points where the curve crosses the x-axis. This can lead to a useful discussion of what is meant by a physically meaningful solution.

Mathematics / Symbolic Mathematics |

Enrichment / Review Materials

Tangent CurveWilliam F. ColemanCompares the slope of the tangent line to the value of the derivative obtained using symbolic differentiation at various points along a particular function.

Mathematics / Symbolic Mathematics |

Enrichment / Review Materials

Visualizing Numerical MethodsWilliam F. ColemanIn this movie the integral of a function is obtained by summing the areas of a number of rectangles, and then is compared to the value of the integral obtained using symbolic integration. It is interesting to note that agreement between the two values of the integral to the fourth decimal place requires over 200 rectangles.

Mathematics / Symbolic Mathematics |

Enrichment / Review Materials

Visualizing Numerical Methods (2)William F. ColemanThese movies are designed to help students visualize various numerical approaches to evaluating functions or solving equations. The methods themselves may be familiar to students from their mathematics courses, but they may have forgotten the material or never made the connection between a statement such as "the derivative of a curve at a given point is the slope of the line tangent to the curve at that point" and the way that one might evaluate such a derivative. All of the movies have VCR-style controls that enable the student to step through them one frame at a time and to move backwards as well as forwards.

Chemometrics

Interactive Raman SpectroscopyWilliam F. ColemanThis is a very simple animation designed to introduce the basics of the vibrational Raman effect. Use the VCR controls to move around the movie.

Raman Spectroscopy |

Enrichment / Review Materials

Newton-RaphsonWilliam F. ColemanIn this movie the user is introduced to the Newton-Raphson method for evaluating the root(s) of a function.

Mathematics / Symbolic Mathematics |

Enrichment / Review Materials

Interactive Electron ConfigurationsWilliam F. ColemanAn application that allows students to drag electrons onto energy levels to construct electron configurations for atoms up to atomic number Ar. The student is responsible for obeying the fundamental rules of quantum mechanics.

Atomic Properties / Structure |

Periodicity / Periodic Table |

Enrichment / Review Materials

Interactive Molecular Orbital DiagramsWilliam F. ColemanHere is an application for constructing the molecular orbital electron configurations of heteronuclear diatomic molecules. Energy level diagrams are given for the two different cases encountered in heteronuclear diatomics of the first short period (Li2 - Ne2). This is a useful tool for having students explore questions of bond order, magnetic properties and numbers of unpaired electrons.

Covalent Bonding |

MO Theory |

Enrichment / Review Materials

Atomic Orbital ShapesWilliam F. ColemanThis applet shows 3-dimensional representations of hydrogenic orbital surfaces. Orbital phase is shown by the different colors. The images are rotatable and scalable. This applet will run very slowly on older, slower machines.

Atomic Properties / Structure |

Enrichment / Review Materials

d Orbitals in an Octahedral Ligand FieldWilliam F. ColemanHere is a page that shows the d orbitals in an axis set. Running the mouse over an orbital reveals the "name" of that orbital. This is good practice for helping students link the name of an orbital to the orientation. This page is linked to an interactive 3-dimensional applet, similar to the one above, that shows the d orbitals in an octahedral ligand field. The user may also click on the name of any one of the d orbitals to obtain a larger 3-dimensional image. The images are rotatable and scalable.

Atomic Properties / Structure |

Enrichment / Review Materials

Heteronuclear Diatomic Molecular Orbital FormationWilliam F. ColemanHere is a set of movies that demonstrates heteronuclear diatomic molecular orbital formation. The orbitals start at a distance where there is little or no interatomic interaction and move to the appropriate bond distance. Orbital phase is shown by the different colors.

Covalent Bonding |

MO Theory |

Enrichment / Review Materials

Interactive Pi Bonding EffectsWilliam F. ColemanThis application demonstrates the effect of pi bonding on the one-electron ligand field splitting in an octahedral. By clicking on the appropriate buttons students can see how D changes when you move from ligands with no pi bonding capability to pi donor and pi acceptor ligands.

Covalent Bonding |

Crystal Field / Ligand Field Theory |

Coordination Compounds |

Enrichment / Review Materials

Radius RatioWilliam F. ColemanThis is a set of animations that demonstrates properties of the spherical holes formed when uniform spheres are packed. Cubic, octahedral and tetrahedral packing arrangements may be examined without anything in the holes,and with the repective holes filled. The sizes of the various holes relative to the spheres being packed are shown, which can lead students into an exploration of the radius ratio concept. An example is given of computing the relative size of an octahedral hole.

Crystals / Crystallography |

Ionic Bonding |

Solids |

Enrichment / Review Materials

Enzyme Activity as a Function of pHPaul KrauseA matched pair of documents providing an introduction to the role of pH in the regulation of enzyme activity. The tutorial document contains all the equations and graphs for students to use to study the role of pH in enzyme kinetics. In the EnzymeExercise twin document all quations are omitted so that students can develop these interactively. The Exercise document is also ideal for display during lecture where the ideas can be developed interactively with the class as a whole.

Enzymes

Solving the Hydrogen AtomTodd M. HamiltonAfter practicing with the particle-in-a-box problem, students solve the H atom symbolically using the derivatives feature in MathCad. The result is an expression for the energy levels of the hydrogen atom. Students will also prove that the radial part of the wavefunction is normalized and explore the concept of an orbital.

Mathematics / Symbolic Mathematics |

Quantum Chemistry

The Effect of Anharmonicity on Diatomic Vibration; A Spreadsheet SimulationWilliam F. Coleman, Kieran F. LimInstructors and students can use this spreadsheet to quickly and easily observe how the shape of a one-dimensional vibrational potential energy curve and its associated vibrational quantum energy levels depend on the anharmonicity. This illustrates the connection between the harmonic (approximation) and anharmonic descriptions of molecular vibrations.

IR Spectroscopy |

Enrichment / Review Materials

Mechanisms That Interchange Axial and Equatorial Atoms in Fluxional ProcessesMarion E. Cass, Henry S. Rzepa, King Kuok HiiThe Berry pseudorotation is a classical mechanism for interchanging axial and equatorial ligands in molecules with trigonal bipyramidal geometry. Teaching this mechanism presents particular pedagogic problems due to both its dynamic and three dimensional character. The approach taken here illustrates these processes using interactive animations embedded in a Web page and overcomes many limitations of a printed page.

Computational Chemistry |

Molecular Properties / Structure |

Nonmetals |

Enantiomers |

NMR Spectroscopy |

Mechanisms of Reactions |

Molecular Mechanics / Dynamics

Computer Simulations of Salt SolubilityVictor M. S. Gil, João C. M. PaivaComputer Simulations of Salt Solubility provides an animated, visual interpretation of the different solubilities of related salts based on simple entropy changes associated with dissolution: configurational disorder and thermal disorder. This animation can also help improve students conceptual understanding of chemical equilibrium before any quantitative interpretation of equilibrium constants is attempted.

Computational Chemistry |

Solutions / Solvents |

Thermodynamics |

Equilibrium |

Precipitation / Solubility

An Animated Interactive Overview of Molecular SymmetryMarion E. Cass, Henry S. Rzepa, David R. Rzepa, Charlotte K. WilliamsAn Animated Interactive Overview of Molecular Symmetry is a series of Web pages designed to help instructors teach molecular symmetry. These pages combine interactive Jmol images and instructional text that allow students to examine and explore the operations and elements that give rise to molecular symmetry.

Crystals / Crystallography |

Group Theory / Symmetry |

Molecular Properties / Structure |

Thermodynamics

Monomer of KevlarWilliam F. ColemanThe WebWare Molecules for July are from the paper Modern Sport and Chemistry: What a Chemically Aware Sports Fanatic Should Know by Giffin, Boone, Cole, McKay and Kopitzke.

Molecular Properties / Structure

C60; a closed shapeWilliam F. Coleman, Randall J. WildmanThe Featured Molecules for August 2002 come from the paper "Generating Closed Shapes From Regular Tilings" by Boo and Mattern. The C60 molecule shown here is an example of a closed [12P:20H] shape.

Molecular Properties / Structure

Sulfur dichloride, SCl2William F. Coleman, Randall J. WildmanThis month's molecule is sulfur dichloride, SCl2. This and other small inorganic molecules are discussed in the article by Matta and Gillespie. They describe electron density in molecules and how to analyze it to obtain information about molecular bonding and structure. Different depictions of electron density in SCl2 and other small molecules emphasize different aspects of their electron density and of the structures of the molecules.

Molecular Properties / Structure

Glycerol, HOCH2CH(OH)CH2OHWilliam F. Coleman, Randall J. WildmanThis month's molecule is glycerol. Consumers often encounter this compound labeled as glycerin, the term used for commercial applications. An ingredient in cleaning products such as soap, and toothpaste, as well as cosmetic, pharmaceutical, and food products, glycerol is one of the many chemicals that keep us clean.

Dibenzyl TerephthalateWilliam F. Coleman, Randall J. WildmanThe WebWare molecule for January is from the article "Chemical Recycling of Pop Bottles: The Synthesis of Dibenzyl Terephthalate from the Plastic Polyethylene Terephthalate" by Craig J. Donahue, Jennifer A. Exline, and Cynthia Warner. Polyethylene terephthalate from 2-liter pop bottles can be recycled by converting it to dibenzyl terephthalate.

Molecular Modeling |

Molecular Properties / Structure

Acetaminophen, Aspirin, and CaffeineWilliam F. Coleman, Randall J. WildmanThe WebWare Molecules for February are from the article, "A General Chemical Laboratory Theme: Spectroscopic Analysis of Aspirin", by Houston Byrd and Stephen E. O'Donnell. In the article, students examine non-prescription medicines containing acetaminophen, aspirin, and caffeine.

Molecular Properties / Structure |

Medicinal Chemistry

Enantiomers of GuaifenesinWilliam F. Coleman, Randall J. WildmanThe WebWare molecules of the month for March are the enantiomers of guaifenesin. The synthesis of the guaifenesin racemate and of the enantiomers is described in the paper by Stabile and Dicks, "Semi-Microscale Williamson Ether Synthesis and Simultaneous Isolation of an Expectorant from Cough Tablets". Guaifenesin [3-(2-methoxyphenoxy)-1,2-propanediol] is used as an expectorant in a number of commercially available cough medicines.

Molecular Properties / Structure

Sucrose and VanillinWilliam F. Coleman, Randall J. WildmanThe WebWare molecules of the month for April relate to the sense of taste. Apple Fool, the JCE Classroom Activity, mentions sucrose and vanillin and their use as flavorings.

Molecular Properties / Structure

Ascorbic Acid and Methylene BlueWilliam F. Coleman, Randall J. WildmanThe WebWare molecules of the month for May are featured in several articles in this issue. "Arsenic: Not So Evil After All?" discusses the pharmaceutical uses of methylene blue and its development as the first synthetic drug used against a specific disease. The JCE Classroom Activity "Out of the Blue" and the article "Greening the Blue Bottle" feature methylene blue and ascorbic acid as two key ingredients in the formulation of the blue bottle. You can also see a colorful example of these two molecules in action on the cover. "Sailing on the 'C': A Vitamin Titration with a Twist" describes an experiment to determine the vitamin C (ascorbic acid) content of citrus fruits and challenges students, as eighteenth-century sea captains, to decide the best fruit to take on a long voyage.

Molecular Modeling |

Molecular Properties / Structure

Penicillin and Vitamin B12William F. ColemanThe WebWare Molecules for July are mentioned in the article "The History of Molecular Structure Determination Viewed through the Nobel Prizes", by Jensen, Palenik, and Suh. One of the recipients discussed, Dorothy Crowfoot Hodgkin, won the Nobel Prize in Chemistry in part for determining the structures of penicillin and vitamin B12.

Molecular Modeling |

Molecular Properties / Structure

Metal Chloride CompoundsWilliam F. ColemanThe WebWare molecules of the month for August stem from the article, "Discovery Videos: A Safe, Tested,Time-Efficient Way To Incorporate Discovery-Laboratory Experiments into the Classroom".

Molecular Modeling |

Molecular Properties / Structure

Crystal Violet, Fluorenone, and FluoreneWilliam F. ColemanThe WebWare molecules of the month for the month of September are discussed in the article by Gail Horowitz, "A Discovery Approach to Three Organic Laboratory Techniques: Extraction, Recrystallization, and Distillation". In the extraction part of the experiment, students use aqueous washes to remove a highly polar colored contaminent (crystal violet) or a nonpolar colored contaminent (fluorenone) from a desired compound (fluorene).

Molecular Modeling |

Molecular Properties / Structure

Quinine and UreaWilliam F. ColemanThe WebWare molecules of the month are discussed in two laboratory articles in this issue. Quinine is studied in the article "A Fluorimetric Approach to Studying the Effects of Ionic Strength on Reaction Rates: An Undergraduate Steady-State Fluorescence Laboratory Experiment" by Stephen W. Bigger, Peter J. Watkins, and Bruce Verity. Urea, a typical protein denaturant, is used as a cosolvent in the article "Transfer Free Energy and the Hydrophobic Effect" by Joseph M. Serafin.

Molecular Modeling |

Molecular Properties / Structure

Amylose and PolystyreneWilliam F. ColemanThe WebWare molecules of the month are amylose and polystyrene, which are examined in JCE Classroom Activity #57: "Pondering Packing Peanuts Polymers". In the activity, students investigate polymers and their chemical composition. The structures below show several repeating units of the two polymers. The helical, 50-unit amylose shows the structure that complexes with iodine to produce the blue charge-transfer complex in the starch iodine test.

Molecular Modeling |

Molecular Properties / Structure

Antiandrogen Prostate Cancer DrugsWilliam F. ColemanThese interactive images are linked to molecular structures or other graphic images from articles in our print Journal. Many articles in the Journal of Chemical Education include molecular structures naturally in a two-dimensional representation. This collection of interactive Chime-based structures are chosen from some of these molecules. While many such Web-based structure collections exist, having the structures in a single location and linked to specific articles in JCE (and vice versa) will benefit both teachers and students.

Molecular Modeling |

Molecular Properties / Structure

Copper and Nickel Complex IonsWilliam F. ColemanThe Featured Molecules this month come from Donald C. Bowmans article A Colorful Look at the Chelate Effect, the final Overhead Projector Demonstrations column edited by the late Doris Kolb. Included in the online collection are all eight isomeric forms of [Ni(en)3]2+, demonstrating the effects of ligand backbone conformation.

Molecular Modeling |

Amino Acids |

Molecular Properties / Structure

Amino AcidsWilliam F. ColemanThe Featured Molecules this month are the 20 standard α-amino acids found in proteins and serve as background to the paper by Barone and Schmidt on the Nonfood Applications of Proteinaceous Renewable Materials. The molecules are presented in two formats, the neutral form and the ionized form found in solution at physiologic pH.

Molecular Modeling |

Amino Acids |

Molecular Properties / Structure

Fountain Pen InkWilliam F. ColemanThis months Featured Molecules are drawn from the paper Chemical Composition of a Fountain Pen by Inkby J. Martín-Gil, M. C. Ramos-Sánchez, F. J. Martín-Gil, and M. José-Yacamán on the composition and stability of inks.

Molecular Modeling |

Molecular Properties / Structure

Lubricating GreasesWilliam F. ColemanThe Featured Molecules for this month all come from the paper "Lubricating Grease: A Chemical Primer" by Craig Donahue. This paper is a rich source of structural examples ranging from small molecules to metal complexes to polymeric species.

Molecular Modeling |

Molecular Properties / Structure

Luminescent Molecular ThermometersWilliam F. ColemanThe Featured Molecules this month come from the paper "Luminescent Molecular Thermometers" by Uchiyama, Prasanna de Silva, and Iwai exploring the many ways that photophysical properties can be used as temperature probes. They introduce a variety of molecule types, many of them now in our molecule collection. Excited states play a central role in this paper and it provides an opportunity to introduce students to some excited state properties.

Molecular Modeling |

Molecular Properties / Structure |

Photochemistry

Microwave-Assisted Heterocyclic ChemistryWilliam F. ColemanThe featured molecules for this month come from the Green Chemistry article, "Microwave-Assisted Heterocyclic Chemistry for the Undergraduate Organic Laboratory" by Musiol, Tyman-Szram, and Polanski.

Molecular Modeling |

Molecular Properties / Structure |

Heterocycles

The Chemistry of Popcorn; Polymers of GlucoseWilliam F. ColemanThe featured molecules this month are all polymers of glucose, and relate to the two papers on the chemistry of popcorn: "Popping Popcorn Kernels: Expanding Relevance with Linear Thinking" by Jordan L. Fantini, Michael M. Fuson, Thomas A. Evans, and "Popcorn What's in the Bag?" by Marissa B. Sherman and Thomas A. Evans.

Molecular Modeling |

Molecular Properties / Structure

Catalysts from the 2005 Nobel Prize in ChemistryWilliam F. ColemanThe 2005 Nobel Prize for Chemistry celebrated molecules that are of great value to researchers, to the broader society, and to chemical educators. Some of those molecules are featured here.

Molecular Properties / Structure |

Molecular Modeling

The Chemistry of Highly Fluorinated CompoundsWilliam F. ColemanThe featured molecules for January come from the paper Fluorous Compounds and Their Role in Separation Chemistry by Maria Angeles Ubeda and Roman Dembinski. This paper explores the use of highly fluorinated compounds as solvents, catalysts, and reagents.

Molecular Modeling |

Molecular Properties / Structure

Perfume Chemistry; Jasmone, α-Damascone, Geraniol, Civetone, and Musk BaurWilliam F. ColemanThe featured molecules for the month of January are some of the natural and synthetic molecules used to create perfumes. The chemistry of perfumes is discussed in the article "Chemistry Perfumes Your Daily Life". Jasmone is a natural component of jasmine and a key component for its odor; α-damascone is a natural component of rose oil; geraniol is a synthetic rose odor; civetone is a macrocyclic musk that used to be obtained from the civet cat; and musk baur is a synthetic molecule with a musky smell.

Molecular Modeling |

Molecular Properties / Structure

Polycyclic Aromatic HydrocarbonsWilliam F. ColemanThe featured molecules for the month of February are a number of polycyclic aromatic hydrocarbons (PAHs) discussed in the article "Fluorescence, Absorption, and Excitation Spectra of Polycyclic Aromatic Hydrocarbons as a Tool for Quantitative Analysis". PAHs are ubiquitous in air, soils, and water as a result of both direct and indirect emissions. PAHs are discharged into environments as byproducts of the combusion of fossil fuels used for transportation and generation of electricity. Other sources of PAH emissions include industrial processes, biomass burning, waste incineration, oil spills, and cigarette smoke.

Molecular Modeling |

Molecular Properties / Structure

Bioorganic Synthesis; Monosodium Glutamate and Other Amino AcidsWilliam F. ColemanThe March featured molecules are discussed in the article "The Monosodium Glutamate Story: The Commercial Production of MSG and Other Amino Acids". This paper provides a number of opportunities for introducing students to the importance of stereochemistry in bioorganic synthesis. The collection here includes all of the relevant molecules in the synthesis of α-amino-ε-aminocaprolactam (ACL). The introduction of two chiral centers in the reaction of cyclohexene with NOCl results in four diastereomers, and it is instructive to ask students to predict the relative abundance of those isomers and the dependence of that distribution on the extent to which the reaction is syn- or anti-addition, and to account for the fact that the resultant oxime, and the ACL, are obtained as racemates.

Molecular Modeling |

Molecular Properties / Structure

The Big Picture; A Classroom Activity for Organic ChemistryWilliam F. ColemanIn the article "The Big Picture: A Classroom Activity for Organic Chemistry", Thomas Poon makes interesting use of the device exploited by Istvan Banyai in his Zoom books to help students of organic chemistry make connections between the molecular world and ways in which those molecules are important in daily life. The paper should have appeal at all levels of science education from the time the idea of molecules is first introduced through college-level courses. Along the way, students will encounter important biological molecules (such as chlorophyll), inks (such as pen ink), CFCs, hydrocarbon fuels, plastics (such as Lexan polycarbonate), and molecules with medical applications (such as aspirin and novocaine).

Molecular Modeling |

Molecular Properties / Structure

Boron ClustersWilliam F. ColemanThe May featured molecules are discussed in the Viewpoints article "Boron Clusters Come of Age". The review paper by Russell N. Grimes on boron clusters reminds us both of the past impact that these interesting structures have had on the development of our understanding of cluster chemistry and on the future development of what one might refer to as "post-fullerene" clusters. The wide range of structures found in this paper admirably illustrate the structural flexibility arising from clusters of a variety of symmetries and degrees of boron replacement with carbon and other atoms.

Molecular Modeling |

Molecular Properties / Structure

Coumarin, Naphthalene, and Additional Polycyclic Aromatic HydrocarbonsWilliam F. ColemanThe featured molecules this month are drawn from two papers. The first, "One-Pot Synthesis of 7-Hydroxy-3-carboxycoumarin in Water", is a Green Chemistry feature by Fringuelli, Piermatti, and Pizzo. The three-dimensional versions of the molecules in the synthesis of the coumarin derivative are directly tied to the reaction scheme included in the paper, opening the possibility of showing large numbers of complex synthetic pathways in this manner.The second paper is "Determining the Carbon-Carbon Distance in an Organic Molecule with a Ruler" by Simoni, Tubino, and Ricchi. This article describes an experiment to determine the size of a naphthalene molecule, using an extension of classic experiments for determining molecular size and Avogadro's number. While the structure of naphthalene will come as no surprise to most students, the molecule collection also includes additional polycyclic aromatic hydrocarbons (PAHs) that can be used to introduce students to the environmental and health issues related to these molecules.

Molecular Modeling |

Molecular Properties / Structure |

Aromatic Compounds

Enantiomer Specificity in PharmaceuticalsWilliam F. ColemanThe molecules of the month this month come from three papers: Demonstration of Enantiomer Specificity of Proteins and Drugs by Gretchen L. Anderson, Incorporation of Medicinal Chemistry into the Organic Chemistry Curriculum by David C. Forbes, and Infusing the Chemistry Curriculum with Green Chemistry Using Real-World Examples, Web Modules, and Atom Economy in Organic Chemistry Courses by Michael C. Cann and Trudy A. Dickneider.The authors of these papers use molecules whose names at least are familiar to the majority of students to introduce important structural and synthetic concepts. A particularly poignant example is that of thalidomide, in which the two enantiomers produce dramatically, and in the case of the S form tragically, different results. In addition to demonstrating enantiospecific reactivity, the thalidomide case is a good starting point for a discussion of how chemists ask questions, what questions we should be asking, and whether or not it is possible to minimize, if not completely eliminate, unintended consequences.

Molecular Modeling |

Molecular Properties / Structure

Chocolate; Theobromine and CaffeineWilliam F. ColemanThe featured molecules this month come from "Chocolate: A Marvelous Natural Product of Chemistry" by Ginger Tannenbaum. As discussed in the article, chocolate is a natural food and is a mixture of many chemical compounds; approximately 400 compounds have been identified in chocolate following fermentation and processing. During processing, a liquid called "chocolate liquor" is formed that is composed of about 55% fat, 17% carbohydrate, 11% protein, and most of the remainder is tannins and ash. Depending on its source, it may also contain theobromine, an alkaloid related to caffeine, in quantities ranging from 0.8% to 1.7%. Caffeine is found in lesser quantities. Theobromine and caffeine are both methyl-xanthines. Theobromine is a smooth muscle stimulant, while caffeine is predominately a central nervous system stimulant. When solidified, the liquor forms bitter (unsweetened) cooking or baking chocolate.

Molecular Modeling |

Molecular Properties / Structure

Alkaloids; Strychnine, Codeine, Heroin, and MorphineWilliam F. ColemanThe featured molecules this month come from the article "The Conversion of Carboxylic Acids to Ketones: A Repeated Discovery" by John W. Nicholson and Alan D. Wilson. The authors describe the repeated discovery of this reaction and illustrate its central role in Woodward's total synthesis of strychnine. Strychnine is a member of a large class of nitrogen heterocycles known as alkaloids, a name derived from the fact that all produce basic solutions in water. Other well-known members of this class of compounds, all of which are pharmacologically active, are nicotine, atropine (deadly nightshade), quinine, lysergic acid, cocaine, and the three structurally similar compounds codeine, heroin, and morphine.

Molecular Modeling |

Molecular Properties / Structure

Chemistry of Blood TypeWilliam F. ColemanThe molecules for this month come from the paper Glycosyltransferases A and B: Four Critical Amino Acids Determine Blood Type by Rose, Palcic, and Evans on structural factors determining blood type. Included are interactive molecule files for the three determinant molecules and the two donors.

Molecular Modeling |

Molecular Properties / Structure

Azulene ChemistryWilliam F. ColemanThe month's featured molecules come from the paper An Azulene-Based Discovery Experiment: Challenging Students To Watch for the "False Assumption" by Charles Garner illustrating some of the chemistry of a substituted azulene. Azulene is a structural isomer of naphthalene and differs from it in several important ways, the most obvious being azulene's intense blue color, which arises from the S0 → S2 transition. Another unusual feature of this molecule is that its fluorescence arises from the reverse of this transition rather than from S1 → S0.

Molecular Modeling |

Molecular Properties / Structure

Moth Repellent ChemicalsWilliam F. ColemanThe featured molecules this month come from the paper The chemistry of moth repellents by Gabriel Pinto. Several of the molecules exhibit interesting structural features that students should explore. Hexachloroethane, not surprisingly, has energy minima in the staggered form that is shown. Students could be asked to look at the models for empenthrin and permethrin to see if they can see similar staggered arrangements in these more complex molecules. Camphor is a good way to introduce strained structures, and students can use the Jmol version of the model to measure bond angles to see if they can identify some of the consequences of this strain. The carbonyl moiety in camphor is interesting as it is non-planar.

Molecular Properties / Structure |

Molecular Mechanics / Dynamics

Menthol SteioisomersWilliam F. ColemanThe JCE Featured Molecules for July come from the paper An Engaging Illustration of the Physical Differences among Menthol Stereoisomers by Edward M. Treadwell and T. Howard Black on the use of commercially available stereoisomers of menthol to illustrate properties of enantiomers and diastereomers. The paper describes the use of four of the eight possible stereoisomers. Structures of all eight stereoisomers are included in this month's molecule collection, labeled by the chirality of the three chiral atoms. In addition to the exercises described in the paper, students can be asked to match the appropriate structures to those shown in the paper, or to generate structures for the isomers that are not discussed.

Molecular Modeling |

Molecular Properties / Structure

Weekly Molecules; A Cure for the 830 a.m. BluesWilliam F. ColemanThe concept of an online molecule of the time period, day, week, or month, as in the case of this column has increased in popularity since the initial Web sites created at a number of British universities in the mid-1990s. The paper, 8:31 a.m. Belly Flop: Attitude Adjustment through Weekly Feature Molecules by Sonya Franklin, Norbert Pienta, and Melissa Fry describes a study of student responses to a molecule of the week program. Some of the results from their surveys of students indicate that the program indeed helps students place the chemistry that they are learning into a broader societal context. Visualizing these molecules in three dimensions helps students who have difficulty going from the two-dimensional drawing to the details of structure and stereo-chemistry. Some of the recent controversy that followed the now infamous comments by Harvard President Lawrence Summers, brought up, once again, the debate over whether men and women have different abilities to visualize in three dimensions. Many of us have seen a lot of evidence that such a difference is not necessarily gender based, but we should be focusing attention on ensuring that such differences are not determining factors for students' success in science. At one time students who could not titrate well were discouraged from becoming chemists. We should make certain that we are not discouraging students for equally unimportant reasons.

Molecular Modeling |

Molecular Properties / Structure

Shikimic AcidWilliam F. ColemanThe molecule for this month comes from the article Isolation of Shikimic Acid from Star Aniseed by Richard Payne and Michael Edmonds. Shikimic acid plays a key role in the biosynthesis of many important natural products including aromatic amino acids, alkaloids, phenolics, and phenylpropanoids. It plays such an important role that one of the key biosynthetic pathways is referred to as the shikimate pathway.

Molecular Properties / Structure

Compounds That Promote Seed GerminationWilliam F. ColemanThe two molecules for this month come from the section Compound in Smoke Provides the Spark for Germination in the article about "Research Advances" by Angela G. King. These molecules have been demonstrated to stimulate seed germination under various conditions. The butenolide moiety is frequently encountered in natural products. An interesting approach to the synthesis of such molecules can be found in this Organic Letters article (accessed January 2005).

Molecular Properties / Structure

Antimicrobial Agents Used on TextilesWilliam F. ColemanThe featured molecules of this month come from the article "Chemistry of Durable and Regenerable Biocidal Textiles" by Gang Sun and S. Dave Worley on the history and chemistry of biocidal textiles for use in the health care industry. All of these molecules can be bound to cellulose in a fabric through chemical modification, illustrating yet again the importance of such polymer-bound substrates in a wide-range of chemistries.

Molecular Properties / Structure

Gertrude Belle ElionBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Erika CremerBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Women in Chemistry |

Enrichment / Review Materials

Gerty Radnitz CoriBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Mary Letitia CaldwellBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

St. Elmo BradyBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Reatha Clark KingBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Women in Chemistry |

Enrichment / Review Materials

Har Gobind KhoranaBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Percy Lavon JulianBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Isabella Lugoski KarleBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Rachel Fuller BrownBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Joyce Jacobson KaufmanBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Irène Joliot-CurieBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Dorothy Crowfoot HodgkinBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

James A. HarrisBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Ellen GleditschBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Lloyd Augustus HallBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Mary Lowe GoodBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Kenichi FukuiBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Rosalind FranklinBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Helen Murray FreeBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Marye Anne FoxBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Mary FieserBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Lloyd Noel FergusonBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Stephanie KwolekBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Yuan Tseh LeeBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Luis Frederico LeloirBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Biographical SnapshotsBarbara A. BurkeThe primary objective of this Only@JCE Online column is to provide information about chemists who have made important contributions to chemistry. A short biographical "snapshot" of each chemist provides basic information about the person's chemical work, gender, ethnicity, and cultural background.

Minorities in Chemistry |

Women in Chemistry |

Enrichment / Review Materials

Marie Maynard DalyBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Water / Water Chemistry |

Enrichment / Review Materials

Kathleen Yardley LonsdaleBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Rachel Abby Holloway LloydBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Agnes Fay MorganBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Koji NakanishiBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Helen M. DyerBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

May Sybil Leslie BurrBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Contrail. A Module from the Physical Chemistry On-Line ProjectFranklin M. C. ChenThe condensation trail, or contrail, that trails behind a jet plane is an everyday observable phenomenon. These manmade cirrus clouds can persist for hours, or even days and can spread over thousands of square kilometers. This is a concern because clouds are major variables that control Earth's atmospheric temperature and climate. Understanding the impact of contrails on Earth's climate is an active area of research. Further, contrail formation can be examined in terms of the operative thermodynamic phenomena. The process of contrail formation involves combustion, cooling, and ice formation, all common topics in the undergraduate physical chemistry curriculum. The project when it is subdivided into separate manageable subjects is a good, comprehensive exercise for physical chemistry students.

Thermodynamics |

Equilibrium

Concept Development Studies in ChemistryJohn S. HutchinsonConcept Development Studies in Chemistry is an on-line textbook for a general chemistry course. Each module develops a central concept in chemistry from experimental observations and inductive reasoning. This approach complements an interactive or active learning teaching approach. The 17 chapters are associated with the general chemistry course taught by the author at Rice University. The author holds a creative commons copyright. Users should see the text home page for details.

Molecular Models of EDTA and Other Chelating AgentsWilliam F. ColemanDeirdre Bell-Oudry presents a variation on an old theme in her paper on using an indirect EDTA titration for sulfate analysis (1). EDTA and (often loosely) related species are this month's Featured Molecules.EDTA is a hexaprotic acid (H6Y2+) having the pKa values given in the featured paper (1). Figure 1 shows a distribution diagram for the EDTA system (2). At the pH of normal waters, the predominant species have one or both of the nitrogen atoms protonated.Complexation, however, requires that both nitrogens be deprotonated and it is generally assumed that the form that complexes with metal ions is Y4−. Structures of several forms of EDTA are included in the molecule collection (Figure 2). These structures are quite flexible having many conformations that are readily accessible at room temperature.An introduction to EDTA chemistry leads to broader questions of metal ion chelation or sequestration. Related chelating agents included in the molecule collection are EGTA, DCTA, NTA, BAPTA, and DTPA. Molecular dynamics and Hartree-Fock calculations on BAPTA (Figure 2) confirm that many conformations, ranging from those with the phenyl rings parallel to one another, to more elongated forms, are essentially isoenergetic in room temperature aqueous solution (3).Also included in the molecule collection are several crown ethers, an isophore (nonactin), and a cryptand. These not only provide students with a glimpse of the types of molecules being employed for metal ion sequestration but open a wide range of topics of current research in a variety of areas of inorganic, industrial, environmental, and biological chemistry.

Aqueous Solution Chemistry

Gladys Ludwina Anderson EmersonBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

Molecular Models of Polymers Used in Sports EquipmentWilliam F. ColemanIn keeping with the 2008 National Chemistry Week theme of Having a Ball with Chemistry, the Featured Molecules this month are a number of monomers and their associated polymers taken from a paper by Sandy Van Natta and John P. Williams on polymers used in making equipment for a variety of high-impact sports (1). The molecules provide students with an introduction to an important area of applied chemistry and also enable them to examine complex structures using the models they have seen applied to small molecules.It is certainly instructive for students to build small polymer fragments using molecular model kits. Holding a model of n-decane, for example, and twisting it in various ways, provides real insight into the multiplicity of conformations available to supermolecules of polyethylene. Computer-based 3-dimensional structure drawing and visualization programs make it possible to construct large oligomers of known polymers and to begin to explore structural properties of new systems. Two such programs, free for academic use, are DSVisualizer and ArgusLab (2). DSVisualizer includes a useful set of tools for building and viewing structures and a clean geometry option that applies a Dreiding-like force field. ArgusLab adds the ability to perform both molecular mechanics and semi-empirical geometry optimization and to display various molecular surfaces. Using ArgusLab, or a similar program, students can explore the relative energies of various conformations of the substances they have built electronically. Students who are being introduced to molecular modeling and the use of more sophisticated software can easily explore the effects of the modeling and convergence parameters on the stable structures that are found, and can begin to explore the difference between global and local minima on a molecular potential energy surface. Using the conformational search program in HyperChem 7.5 on a tetramer of vinyl chloride (terminated with H; of SRRS stereochemistry; only CCCC torsions varied), approximately half of the 500 structures examined fell within 6 kcal/mol of the lowest energy structure (3). This number would increase significantly if other torsion angles were included.The use of computational software allows us to introduce students in introductory chemistry to the idea of multiple conformations, which is so important in biochemistry and much of organic chemistry. In teaching ideas behind conformational stability care should be taken when attributing conformational stability solely to non-bonded repulsions between peripheral atoms on adjacent carbon atoms. Weinhold and co-workers have recently presented strong evidence that the stability of the staggered conformer of ethane relative to the eclipsed form arises from more favorable interactions of C-H sigma bonding orbitals on adjacent carbons (4). The multiplicity of such interactions could well be responsible for conformational stability in more complex systems. Any discussion of conformational stability should also introduce students to the ultimate conformational problem, the folding of proteins and to the Folding@home project (5).

Molecular Models of Compounds in LightsticksWilliam F. ColemanThe article Glowmatography, by Thomas S. Kuntzleman, Anna E. Comfort, and Bruce W. Baldwin, is the source of this month's Featured Molecules (1). Three molecules from the paper have been added to the collection and several rhodamine derivatives were featured in the November 2007 column (2).The energy transfer agent in the lightsticks is 1,2-dioxetanedione, a cyclic peroxide and high energy dimer of carbon dioxide. Students at all levels would be interested to learn that the chemistry of a toy can be used in a wide variety of applications. For example, 1,2-dioxetanedione embedded in nanoparticles has recently been used to image hydrogen peroxide in cells (3).A number of polyaromatic compounds are included in Table 1 of the source paper (1). Rubrene, 5,6,11,12-tetraphenyl-naphthacene, when optimized at the PM3 level, shows an interesting chiral twist to the napthacene backbone of about 37Â°. We find that twist to be present, but reduced to about 10Â° at the HF/6-31G(d) level, and a similar magnitude at the B3LYP/6-31G(d) level. A more complete DFT study is underway as our results do not agree with those of KÃ¤fer and Witte who find a somewhat larger twist angle (4). Those authors point out that the crystal structure of rubrene shows no twist. Rubrene also has many uses other than entertainment. It is an organic semiconductor used in LEDs, solar cells, and transistors, and has recently been shown to produce interesting self-assemblies on metal surfaces (5).Another polyaromatic compound, 5,12-bis(phenylethynyl)naphthacene, shows the expected planar structure and the molecular orbitals are consistent with a high degree of delocalization. This compound has been used to activate the bleaches in commercial teeth-whitening products (6).Other molecules from Table 1 (1) would provide students the qualitative experience of leaning about applications beyond the lightstick and the quantitative experience of optimizing structures to explore the ways in which the various substituents pack around the polycene backbone.

Tetsuo NozoeBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Minorities in Chemistry |

Enrichment / Review Materials

Molecular Models of Volatile Organic CompoundsWilliam F. ColemanThis month's Featured Molecules come from the Report from Other Journals column, Nature: Our Atmosphere in the Year of Planet Earth, and the summary found there of the paper by Lelieveld et al. (1, 2) Added to the collection are several volatile organic compounds (VOCs) that are emitted by a variety of plants. The term VOCs is a common one in environmental chemistry, and is interpreted quite broadly, typically referring to any organic molecule with a vapor pressure sufficiently high to allow for part-per-billion levels in the atmosphere. Common VOCs include methane (the most prevalent VOC), benzene and benzene derivatives, chlorinated hydrocarbons, and many others. The source may be natural, as in the case of the plant emissions, or anthropogenic, as in the case of a molecule such as the gasoline additive methyl tert-butyl ether (MTBE).The oxidation of isoprene in the atmosphere has been a source of interest for many years. Several primary oxidation products are included in the molecule collection, although a number of isomeric forms are also possible (3).The area of VOCs provides innumerable topics for students research papers and projects at all levels of the curriculum from high-school chemistry through the undergraduate courses in chemistry and environmental science. Along the way students have the opportunity for exposure to fields such as epidemiology and toxicology, that may be new to them, but are of increasing importance in the environmental sciences. The MTBE story is an interesting one for students to discover, as it once again emphasizes the role that unintended consequences play in life. An exploration of the sources, structures, reactivity, health and environmental effects and ultimate fate of various VOCs reinforces in students minds just how interconnected the chemistry of the environment is, a lesson that bears repeating frequently.

Molecular Modeling |

Atmospheric Chemistry

Emma Perry CarrBarbara A. BurkeThis short biographical "snapshot" provides basic information about the person's chemical work, gender, ethnicity, and cultural background. A list of references is given along with additional WWW sites to further your exploration into the life and work of this chemist.

Women in Chemistry |

Enrichment / Review Materials

AcronymsHans J. ReichAbout 150 common acronyms are listed along with their full names and structures.

Nomenclature / Units / Symbols

Named ReactionsMichael B. SmithThis Web site lists 95 of the most important named reactions in organic chemistry. Each is linked to a Web page that gives the primary reference and equations for one or more recent literature examples that illustrate the use of the reaction.

Nomenclature / Units / Symbols |

Reactions

Named ReagentsHans J. ReichThis convenient list provides structures of more than 160 common reagents used in organic chemistry that are often referred to by the originator's name, by an acronym, or by a trade name.

Nomenclature / Units / Symbols |

Reactions

Named Rules and EffectsHans J. ReichConcise descriptions and structures of a number of named effects, rules, stereochemical models and hypotheses' from Baldwin's rules to the Zimmerman-Traxler transition state are given.

Bordwell pKa Values in DMSOF. BordwellThe late F. Bordwell of Northwestern University measured the pKa values of thousands of organic compounds. This Web site makes some of the data he measured conveniently available to the chemical community, and provides literature references to the published data (the Web site also includes much unpublished data).

WebWareWilliam F. Coleman, Edward W. FedoskyComputer programs and documents are written by conscientious chemistry educators worldwide to aid students. We make these tools available so they may be used not only in the classroom or laboratory, but also in the student's dorm room, home, or local campus computer lab. These tools may include Java applets, dynamic HTML (DHTML) pages, virtual reality (VRML) documents, QuickTime and Flash movies, animated gifs, and applications that can be used over the Internet with helper programs such as Excel. JCE WebWare maintains two collections of WWW-based learning aids: a peer-reviewed collection and an open-review collection. The table below summarizes the differences between the collections.

JCE LrnComOnlineThe goal of the JCE LrnComOnline feature column is to promote creation, dissemination, and utilization of well-crafted online instructional modules that span the chemistry curriculum. Online modules are multi-week projects that engage students in learning experiences that cut across traditional institutional or disciplinary boundaries. Modules are designed to foster and encourage both intercollegiate and intracollegiate collaborations both among students and among teachers. Students working on a project constitute a virtual learning community, connected through information technology. The same applies to faculty mentors. Goals of the JCE LrnComOnline feature include enhancing subject-matter learning, improving students ability to collaborate effectively, fostering collaborations among faculty, encouraging research into teaching methods, and providing modular resources in an easily accessible format.

JCE Featured MoleculesWilliam F. Coleman, Randall J. WildmanThese interactive images are linked to molecular structures or other graphic images from articles in our print Journal. Many articles in the Journal of Chemical Education include molecular structures naturally in a two-dimensional representation. This collection of interactive Chime-based structures are chosen from some of these molecules. While many such Web-based structure collections exist, having the structures in a single location and linked to specific articles in JCE (and vice versa) will benefit both teachers and students. In addition to static images, two fully manipulable versions (Jmol, MDL Chime) of these molecules are available.

Molecular Modeling |

Molecular Properties / Structure |

Enrichment / Review Materials

JCE Cheminfo; OrganicCollection Curator; Hans J. ReichJCE ChemInfo: Organic is a collection of Web pages containing information useful to teachers, researchers, and students in organic chemistry, biochemistry, and medicinal chemistry. The pages have been selected for ease of use, broad applicability, and quality of coverage. Topics will include structural information, organic reactions, nomenclature, physical properties, and spectroscopic data. These Web pages will be updated when possible and additional Web pages will be added as they become available.

Cl2O4 in the StratosphereDavid M. Whisnant, Lisa Lever, Jerry HoweThe depletion of ozone in the stratosphere is caused chiefly by ozone reacting with chlorine and bromine from industrially manufactured gases. Several small chlorine oxide molecules are involved in the catalytic cycles that lead to the destruction of ozone. In this comprehensive project, students use computational chemistry to investigate a larger chlorine oxide, Cl2O4.

Balance (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchBalance: this is a resource in the collection "ChemPages Laboratory Resources". A laboratory balance is used to measure the mass of reagents or laboratory equipment. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Barometer (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchBarometer: this is a resource in the collection "ChemPages Laboratory Resources". A mercury barometer is used to measure atmospheric pressure. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Bulb Standard (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchBulb Standard: this is a resource in the collection "ChemPages Laboratory Resources". A standard pipet bulb is used to draw a liquid into any type of pipet. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Bulb 3-Way (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchBulb 3-Way: this is a resource in the collection "ChemPages Laboratory Resources". A three-way pipet bulb is used to draw a liquid into any type of pipet. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Buret (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchBuret: this is a resource in the collection "ChemPages Laboratory Resources". A buret is a glass tube with graduations that can be used to determine the volume of solution added to a receiving vessel. The buret is designed to accurately deliver between 30 and 50 mL of a solution. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Centrifuge (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchCentrifuge: this is a resource in the collection "ChemPages Laboratory Resources". The centrifuge is used to separate a solid from a solution quickly. A centrifuge is used for small-scale separations; typically the volume is less than 5 mL. Larger volumes of mixtures can be separated by filtration. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Chart Recorder (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchChart Recorder: this is a resource in the collection "ChemPages Laboratory Resources". A chart recorder can be used to record data versus time. Chart recorders are commonly used to record chromatographic data. (Though computer data acquisition is increasingly more common.) The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Chromatography, Gas (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchChromatography, Gas: this is a resource in the collection "ChemPages Laboratory Resources". Gas chromatography is a method for separating the components of a solution and measuring their relative quantities. It is a useful technique for chemicals that do not decompose at high temperatures and when a very small quantity of sample (micrograms) is available. The use of gas chromatography is limited by the decomposition temperature of the components of the mixture and the composition of the column. Most columns cannot withstand temperatures greater than 250-350 °C. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Stoichiometry (Netorials)Rachel Bain, Mithra Biekmohamadi, Liana Lamont, Mike Miller, Rebecca Ottosen, John Todd, and David ShawStoichiometry: this is a resource in the collection "Netorials". Stoichiometry shows how to balance chemical equations, deal with limiting reactants, computing yelds, working with molarity and different concentrations as well as the use of stoichiometry principles in the chemical analysis of a mixture. The Netorials cover selected topics in first-year chemistry including: Chemical Reactions, Stoichiometry, Thermodynamics, Intermolecular Forces, Acids & Bases, Biomolecules, and Electrochemistry.

Stoichiometry

Intermolecular Forces (Netorials)Rachel Bain, Mithra Biekmohamadi, Liana Lamont, Mike Miller, Rebecca Ottosen, John Todd, and David ShawIntermolecular Forces: this is a resource in the collection "Netorials". In this resource there is a review of Lewis structures, molecular geometry, electronegativity, or molecular polarity. After that, you can learn about the forces of attraction that exist between molecules. This module explores London forces and dipole-dipole forces (including hydrogen bonds). The Netorials cover selected topics in first-year chemistry including: Chemical Reactions, Stoichiometry, Thermodynamics, Intermolecular Forces, Acids & Bases, Biomolecules, and Electrochemistry.

Noncovalent Interactions

Acids and Bases (Netorials)Rachel Bain, Mithra Biekmohamadi, Liana Lamont, Mike Miller, Rebecca Ottosen, John Todd, and David ShawAcids and Bases: this is a resource in the collection "Netorials". In this module there is an introduction to the chemical properties of acids and bases. Afterwards, the sections include topics such as Molecular Structures of Acids and Bases, Ionization constants, properties of salts, buffers and Lewis theory of Acids and Bases. The Netorials cover selected topics in first-year chemistry including: Chemical Reactions, Stoichiometry, Thermodynamics, Intermolecular Forces, Acids & Bases, Biomolecules, and Electrochemistry.

Acids / Bases

A Method of Visual Interactive RegressionMichelle S. Kim, Maureen Burkart, Myung-Hoon KimOver the past decade many colleges and universities have placed increased emphasis on having students develop statistical and data analysis skills in a range of disciplines. Some institutions now require that all students complete at least one course with a strong component of data analysis, whether the data are from chemical experiments, the census, or some other source. As chemists, one of our concerns should be to ensure that students view data analysis as an integral part of any quantitative experiment, and, as far as possible, do not treat this process as a black box. The authors of A Method of Visual Interactive Regression, a spreadsheet application, have developed a visual approach to linear least-squares curve fitting that drives home the idea of minimizing the sum of the squares of the deviations in order to find the best fit to a set of data that are being described by a linear relationship. For many students these visualizations are likely to persist a great deal longer than the mathematical derivations of the equation for the slope and the intercept. The visualizations will provide a useful connection between a set of equations and the buttons on a calculator or the insertion of a trendline in a spreadsheet.

Chemometrics

Introduction of Aquatic Chemistry in General Chemistry Curriculum;Spreadsheet Calculation ApproachesChulsung KimFundamental aquatic chemistry concepts may be introduced in general chemistry classes by computing ionization fractions and buffer intensity of aqueous phase carbonate systems. This Excel spreadsheet may used to build graphic presentations of a titration curve, distribution diagram, and buffer intensity as a function of pH. Accompanying activities are designed to enhance the concepts of acid-base equilibrium through exploring the relationship between pKa/pKb, pH of the solution, ionization fractions, and buffer intensity, and to exercise students graphing skills.

Acids / Bases |

Aqueous Solution Chemistry |

pH |

Titration / Volumetric Analysis |

Water / Water Chemistry |

Equilibrium

A Graphical User Interface for PC GAMESSWayne P. AndersonGAMESS is a set of computational chemistry tools available free for several computing platforms. Using the set of tools described here along with the pcgRun tool provided allows these tools to be used on the ubiquitous Windows PC with a graphic interface preferred by many of us over the command line.

Computational Chemistry |

Molecular Properties / Structure |

Undergraduate Research |

Enrichment / Review Materials

Mage; A Tool for Developing Interactive Instructional GraphicsStephen F. PavkovicMage is a graphics program especially well suited for visualizing three-dimensional structures of proteins and other macromolecules. It is an important tool for biochemists and finds many applications in biochemistry courses. We utilize Mage to create interactive instructional graphics of potential use in a wider range of undergraduate chemistry courses, and present some of those applications here.

Crystals / Crystallography |

Group Theory / Symmetry |

VSEPR Theory |

Molecular Properties / Structure |

Stereochemistry |

Proteins / Peptides

Werner and Jørgensen Bond TheoryDavid M. Whisnant, Laura YindraThis simulation begins in the period around 1870 when chemistry is beginning to be organized. The concept, introduced by Kekulé and Couper, of tetravalent carbon atoms capable of linking to each other has permitted the rise of structural concepts in organic chemistry.

The Evolution of Bond TheoryDavid M. Whisnant, Laura YindraIn chemistry lectures we have little time to discuss the history of chemistry. This simulation begins with the development of valence concepts in the 19th century. We will step back into the 19th century to see how theories of chemical combination changed during that time.

Nomenclature / Units / Symbols |

Valence Bond Theory

General Chemistry Multimedia ProblemsDavid M. WhisnantGeneral Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Acids / Bases |

Atomic Spectroscopy |

Calorimetry / Thermochemistry |

Isotopes |

Magnetic Properties |

Phases / Phase Transitions / Diagrams |

Surface Science |

Thermodynamics |

Equilibrium |

Oxidation / Reduction

Chemistry Formatter Add-ins for Microsoft Word and ExcelChristopher KingA chemistry formatter is software that does some of the formatting a chemist would otherwise have to do by hand. Chemistry formatters for Microsoft Excel and Word are provided that perform the five functions described below. 1. The appropriate numbers in a chemical formula are subscripted, as in H2O. 2. The asterisk is replaced by · (to indicate waters of hydration or a radical). 3. Charges are superscripted. 4. -> is converted to →. 5. Numbers in the form of 3.2E8 are converted to 3.2 × 108.

Gas Phase AcidityThis site provides a very comprehensive collection of thermodynamic data selected by the scientists at the National Institute of Standards and Technology (NIST).

Elementary BingoRobert M. Hanson, Ira M. HansonElementary Bingo is a simple Web page that creates Bingo cards for a classroom or social event activity associated with review and/or learning of the names and symbols of the elements. The essential element of the site is that every time the page is reloaded or printed, a unique set of Bingo cards is produced. As in ordinary Bingo, players receive Bingo cards that have chemical symbols. An announcer picks elements out of a hat (or beaker) and announces a chemical name. Players place markers on the symbol for that element if they have it on their card. Once a player has five across, five down, or five diagonally, they announce, "Bingo!" Their card is checked to see if, indeed, they do have the announced elements present.

Nomenclature / Units / Symbols |

Periodicity / Periodic Table |

Enrichment / Review Materials

Molecular Model of Creatine SynthesisWilliam F. ColemanThe featured molecules for this month come from the paper Creatine Synthesis: An Undergraduate Organic Chemistry Laboratory Experiment by Andri Smith and Paula Tan on the synthesis of creatine in introductory organic chemistry. This synthesis is sufficiently straightforward to be used in non-majors and general chemistry courses. The structures illustrate some of the limitations associated with the computation of molecular structure. The two adenosine phosphates ADP and ATP exhibit a large number of conformations due to rotation of the adenine system around the bond to the ribose ring, multiple rotational conformations in the phosphate groups, the ionic state of the compound, and the interaction with the solvent or another species such as creatine. The structures that are given for ADP and ATP are derived from PM3MM calculations and are very similar to those derived using the UFF force field. Sarcosine, creatine, and creatine phosphate were treated using the model chemistry B3LYP/6-31+G(d). Perhaps the most interesting structural feature is found in the small molecule cyanamide. Observant students might notice in the Web-based structure that the NCN grouping in cyanamide is non-linear, with an angle of about 177°. This is found for essentially all levels of theory we examined up through the G2 combined model. For students who do notice this deviation from linearity it is useful to ask them whether they are surprised, ask them to defend their answer, send them to the literature to see whether such behavior is seen for cyanamide in other phases (it is), and finally to speculate on possible explanations for the observed non-linearity.

Molecular Modeling |

Molecular Properties / Structure

Molecular Models of Candy ComponentsWilliam F. ColemanThis month's Featured Molecules come from the paper "A Spoonful of C12H22O11 Makes the Chemistry Go Down: Candy Motivations in the High School Chemistry Classroom" by Fanny K Ennever on using candy to illustrate various principles. They include sucrose and the invert sugar that results from the hydrolysis of sucrose. Students should look for structural similarities between sucrose and the hydrolysis products glucose and fructose, and verify that all three are indeed hydrates of carbon. They should also inspect the models to see whether the position of the substituents in the five and six membered rings are the same in the sucrose and in the hydrolysis products. Also included are two esters important in fruit flavoring of candies. Flavor and aroma are inexorably intertwined in the taste experience and no single compound is responsible for that experience. Methyl cinnamate, included here, is one of over 100 esters, and over 300 compounds, involved in the taste of strawberries (1). Isoamyl acetate is a major component of the taste of bananas. Lastly, chocolate, perhaps nothing else need be said. There is a great deal of confusion in the popular press and on the internet between theobromine, found in cocoa beans, and caffeine. Both molecules are included here and students should easily see why the two might be confused. Consequently there are many exaggerated claims about caffeine in chocolate. An interesting assignment would be for teams of students to find reliable data on the physiological effects of these similar molecules, and to find good analyses on the actual level of caffeine in cocoa beans, versus the amount added in the candy production process, if any.

Consumer Chemistry |

Molecular Modeling

Molecular Model of trans-3-(9-Anthryl)-2-Propenoic Acid Ethyl EsterWilliam F. ColemanThe Featured Molecules this month come from the paper by Nguyen and Weisman on solvent-free Wittig reactions and the stereochemical consequences of crowding in the transition state. The molecules include those pictured in the paper as well as the cis-isomer of 3-(9-anthryl)-2-propenoic acid ethyl ester. All structures were optimized at the B3LPY/6-31G* level. In the case of ethyl cinnamate, the cis-isomer is slightly more stable thermodynamically than the trans isomer, lending further support for the argument that the observed product distribution arises from the energetics of the transition state.

Molecular Modeling |

Molecular Modeling |

Molecular Mechanics / Dynamics

Molecular Model of ZinconWilliam F. ColemanThe Featured Molecules this month are the tautomeric forms of the colorimetric reagent zincon, used in the paper by Maria Mar Areco, Maria dos Santos Afonso, and Erika Valdman on the bioabsorption of zinc, and by extension other metal ions, by seaweed. The structures presented have been calculated at the DFT/6-31G(d) level using the B3LYP functional. These structures represent energy minima, but not necessarily global minima. The structures could be used as an introduction to the concept of tautomerism, with students being asked to develop a definition of the term based on their observations of the difference(s) in linkage in the two forms. An intramolecular hydrogen bond is found in each structure, and introductory chemistry students could be encouraged to look for these structural features in molecules that are more complex than those typically encountered to introduce hydrogen bonding. More advanced students could use computational techniques to explore the energy differences between the two forms, and compare those differences to the ones observed between more traditional keto/enol examples.

Calorimetry / Thermochemistry |

Water / Water Chemistry |

Biological Cells

Molecular Models of Plant HormonesWilliam F. ColemanThe paper "Synthesis of Plant Auxin Derivatives and Their Effects on Ceratopteris richardii" by Corey E. Stilts and Roxanne Fisher describing an experiment begun in the organic labs and completed in a biochemistry cell biology lab provides the featured molecules for this month. The molecules in Figure 1 of that paper have been added to the collection. There is nothing particularly surprising about their structures, but students might be interested in seeing whether they can determine any structure/regulating effect relationships as the number of synthesized auxin derivatives grows. Additionally, students with little or no biochemistry background might wish to explore other systems that act as growth regulating hormones in plants, as an introduction to the variety of molecular structures that can display such bioactivity. Such molecules range from the very simple, ethene, to the adenine-derived cytokinins (an example of which, zealtin, is shown here) and the brassinosteroids. Brassinolide, a commonly occurring brassin, is also shown. These latter two structures have also been added to the molecule collection. All of the structures have been optimized at the HF/6-31G(d) level.

Synthesis |

Biological Cells |

Hormones |

Bioorganic Chemistry

Molecular Models of Compounds in Maple SyrupWilliam F. ColemanThis month's issue of J. Chem. Educ. includes articles by David Ball dealing with the chemical composition of honey (1) and maple syrup (2). The JCE Featured Molecules for this month are drawn from those papers. In prior months we have included sucrose, glucose, and fructose (3), and all of the naturally occurring amino acids (4) in the molecule collection. This month we add the molecules identified in Table 4 of ref 2 as probable contributors to the taste of maple syrup. This group of molecules could serve easily as a starting point for a variety of student activities in the area of taste. Students in non-majors courses could be asked to identify structural similarities and differences among the various molecules and could be introduced to functional groups. Students could look for other foods in which some of these molecules are found, and could begin to develop a list of molecules contributing to flavor. In the penultimate paragraph of the maple syrup paper there is a list of substances used as flavoring agents in artificial (maple) syrup. What molecules are in fenugreek and lovage that might be important in flavoring? What are the structures of the other molecules in that paragraph and what, if any, structural features do they have in common with the featured molecules? Students in organic or biochemistry courses could begin to explore the chemistry of taste in more detail. Good starting points for this work are The Chemistry of Taste: Mechanisms, Behaviors, and Mimics by Peter Given and Dulce Paredes (5) and the Chemical and Engineering News Web site (6), which includes a number of articles on this subject.

Descriptive Chemistry |

Solutions / Solvents |

Food Science |

Plant Chemistry

HCP LayersWilliam F. ColemanAn animation showing both the top and side views when three layers of spheres are arranged in a hexagonal close-packed array The user can control the animation through vcr controls.

Crystals / Crystallography |

Molecular Properties / Structure |

Solids |

Enrichment / Review Materials

Quartz and CholesterolWilliam F. Coleman, Randall J. WildmanThe WebWare molecules of the month for June are from two articles in this issue. The article, "Cement: Its Chemistry and Properties", featured on the cover, dicusses the constituents of cement. Silica is one of the main components of cement, and the most common form of pure silica (SO2) is α-quartz. In "Bromination and Debromination of Cholesterol: An Inquiry-Based Lab Involving Structure Elucidation, Reaction Mechanism, and 1H NMR", Grant and Latimer describe an experiment suitable for upper-level organic chemistry students.

SunscreensWilliam F. ColemanReinforcing the "Heath and Wellness" theme of National Chemistry Week 2004, the featured molecules for this month are all found in commercial sunscreens, or in the synthesis of sunscreen materials. The paper by Stabile and Dicks introduces students of organic chemistry to the synthesis of cinnamate esters used in sunscreen products. Several of the papers referenced by those authors, most notably a paper by Doris Kimbrough (J. Chem. Educ. 1997, 74, 51?53), present the structures of additional sunscreen components. Although the details of the synthesis are beyond the scope of most introductory courses, these molecules present an excellent opportunity for introducing students to the absorption of radiation that is far more relevant to their lives than the line spectra of hydrogen and other atoms. Such a discussion could be extended to include more delocalized dyes such as those frequently studied in physical chemistry courses as a test of particle-in-a-box models, and students could be asked about those molecules as sunscreens, which raises an interesting intersection between aesthetics and spectroscopy.

Consumer Chemistry

Nanoscale Molecular TweezersWilliam F. ColemanThe featured molecules for this month are drawn from the "Research Advances" column by Angela G. King, and represent some of the structures from the research on molecular tweezers (published in J. Am. Chem. Soc. 2004, 126, 8124). The structures below are based on the figure on page 1690 showing two types of receptors that switch between U and W shapes upon coordination of soft metal cations, acting in the manner of mechanical tweezers. When viewing these molecules in Chime you must render in ball and stick or space filling modes in order to see the incorporated metal ions. In several cases the torsion angles connecting the anthracene substituents to the rest of the molecule are not well defined and have been drawn as either coplanar or orthogonal to the central ring system. At a moderate level of theory, the torsion angle in those instances where it has been set to 90° displays a broad minimum ranging for 50?130°.

Nanotechnology

Nicotine Smoke ChemistryWilliam F. ColemanThe featured molecules this month come from the paper Using "Basic Principles" To Understand Complex Science: Nicotine Smoke Chemistry and Literature Analogies by Jeffrey Seeman detailing some of the complexities involved in the volatilization of two alkaloids, nicotine and cocaine. Students could be asked to identify how chemistry is involved in the various steps described in the paper, and most beginning students will be surprised to learn just how complex a process the volatilization of a molecule such as nicotine is.

The Chemistry of CoffeeWilliam F. ColemanThe paper Our Everyday Cup of Coffee: The Chemistry behind Its Magic by Marino Petracco provides a hearty blend of molecules for this month. The author deals with coffee at a number of different levels ranging from the economic and social to the still perplexing questions of flavor and aroma. The associated molecules demonstrate a range of structural features that students will benefit from examining in three dimensions.

Bioorganic Chemistry

Photosystem II Oxygen-Evolving ComplexWilliam F. ColemanBoth introductory texts and texts for upper-level inorganic chemistry courses are shifting the emphasis in their coverage of transition metal chemistry from classical Werner complexes to those that exhibit some form of catalytic activity. This is of particular importance to bioinorganic chemistry, a now mature area of the science, but one that is still underrepresented in the undergraduate curriculum. Derrick L. Howard, Arthur D. Tinoco, Gary W. Brudvig, John S. Vrettos, and Bertha Connie Allen address this issue in their paper Catalytic Oxygen Evolution by a Bioinorganic Model of the Photosystem II Oxygen-Evolving Complex by a dimanganese complex that is proposed as a model for the four-manganese center in Photosystem II. The featured molecules for May are the model compound in the proposed mechanism for oxygen production.

Transition Elements

Molecular Model of TubocurarineWilliam F. ColemanCurare, the Karib name for the plant from which this molecule is derived, is used in traditional South American medicine and hunting because it is a muscle relaxant. The three papers by Brunsvold and Ostercamp (1, 2, 3) provide us with an abundance of candidates for Featured Molecules this month. All of the major compounds highlighted in the papers, and many of the intermediates in the synthetic schemes, have been added to our collection. Students should note the structural similarities of the various barbiturate species and of the steroid-based compounds, as well as the interesting proto-cage structure of curare. Careful examination of the conformation of the alkyl groups in various of the molecules, when looked at as Newman projections, should convince students that their expectations about staggering substituents on adjacent tetrahedral-like carbon atoms are met in the computations. However, they should also be aware that recent work casts some doubt on the traditional explanation for that staggering (1). Charged species are presented in the collection in ionic form, without counterions (those are given in the papers), and all species except curare and atricurium besylate (molecule 40 in the third paper) were optimized at either HF/631-G(d) or B3LYP/631-G(d). The latter two molecules were optimized using HF/STO-3.

Bioorganic Chemistry

Molecular Models of DNAWilliam F. ColemanThe featured molecules this month come from the paper by David T. Crouse on the X-ray determination of the structure of DNA. Given that most students are aware of the double helix, it seems appropriate to back up a little and examine the components that give rise to this structure. Accordingly, the molecule collection includes: Purine and pyrimidine, structural precursors of the four bases found in DNA: cytosine (C), thymine (T), adenine (A), and guanine (G) The four corresponding deoxyribonucleosides The four deoxyribonucleotides (the nucleoside monophosphates) A two-base-pair fragment showing the AT and GC hydrogen-bonded complements Several small 24-base-pair DNA fragments polyAT, polyGC, and a random array of bases. The DNA fragments provide a good opportunity to have students explore features of the Jmol and Chime menus. Using the Jmol menu as an example (right-click on the structure to bring up the menu) students can use the measuring tools to get an idea of the length of a complete turn in the DNA, the relative widths of the major and minor grooves, and the diameter of the helix. They can use the coloring schemes to detect the various base pair combinations, and learn to read the code for the random sequence. In Chime they can use the Shapely coloring scheme for this same purpose. Exploring other aspects of the menu will allow students to present the molecules in the various forms, including ribbon and cartoon views. In RNA, thymine is replaced by uracil, and the sugar moiety has an axial hydroxyl group on the carbon atom adjacent to the base binding site (the 2? carbon). The structures of uracil and of uridine monophosphate are included in the molecule collection. Students can use the Web to download and examine more complex DNAs using a site such as the Nucleic Acid Database at Rutgers University.

Nucleic Acids / DNA / RNA

Molecular Models of Ruthenium(II) Organometallic ComplexesWilliam F. ColemanThe featured molecules for this month come from the paper "Experiments in Thermodynamics and Kinetics of Phosphine Substitution in (p-Cymene)RuCl2(PR3)" by Ozerov, Moura, and Hoffman in which they study the reactions of a number of "piano stool" complexes of ruthenium(II). The synthesis of compound 2a offers students an alternative to the preparation of ferrocene if they are only preparing one metal-arene complex, and the use of the (p-cymene)RuCl2 dimer as a starting material introduces them to a compound that has become important for the synthesis of a number of ruthenium catalysts. Two structures are found for the dimer in the gas phase, one with the chlorides cis to one another and a more stable form with the chlorides trans. DFT calculations using the LanL2MB basis set and the B3LYP functional in Gaussian 03 (1) show the trans form to be about 90 kJ/mol more stable than the cis form. The structures of the trans form of the dimer and of compound 2a are presented in 2 formats with bonds from the ruthenium ion to all of the carbons in the aryl ring and with a single line to a ghost atom in the center of the ring. These are the two common ways of representing such structures but students should be made aware that the overall coordination about the ruthenium in both the dimer and in compound 2a is octahedral, and should look at the structures to convince themselves of that fact. It is also instructive to look at compound 2a, and the other piano stool complexes that are made in the paper, to see how deceptive representation of the triphenylphosphine moiety as PR3 is in terms of the stereochemical bulk of that group.

Organometallics

Molecular Models of ResveratrolWilliam F. ColemanThe featured molecules this month are from the paper "Resveratrol Photoisomerization: An Integrative Guided-Inquiry Experiment" by Bernard, Gernigon, and Britz-McKibbin exploring trans to cis photoisomerization in resveratrol. Examination of Figure 1 in that paper, where the hydrogen atoms have been omitted, might lead one to conclude that the structures are relatively straightforward. These isomers provide students an excellent opportunity to test their ability to take a two-dimensional representation and envision the three-dimensional structure of the molecule and to consider the competing factors that might lead to the three-dimensional structures being non-planar. The two-dimensional models focus attention on the possibility of extended pi-electron delocalization. Addition of the hydrogen atoms clearly suggests that delocalization will compete with non-bonded H-H repulsions in the cis isomer. Further examination of the trans isomer shows that such non-bonded interactions are, in what one might call a first-order approximation, like those in biphenyl interactions that lead biphenyl to be non-planar in both the gas phase and in a variety of solvents. The backbone of the trans isomer of resveratrol, trans-stilbene, has been the subject of a number of theoretical and experimental investigations (1, 2). In general, Hartree-Fock calculations predict a non-planar geometry for this molecule while Density Functional Calculations, using the same basis sets, predict an essentially planar structure. Spectroscopic evidence supports a temperature-dependent structure for trans-stilbene with the molecule being planar at low temperature and non-planar at high temperatures. Our calculations on trans-resveratrol produce similar results. Hartree-Fock calculations using the 6-31G** (6- 31G(d,p)) basis set predict a dihedral angle of approximately 24 degrees between each ring and the central carbon-carbon double bond. This result is consistent with the reported value of 23 degrees using the 6-31G* basis set. We also find that DFT calculations using the B3LYP functional and the 6- 31G** basis set, lead to a planar configuration. We include several versions of trans-stilbene and trans-resveratrol in the molecule collection so that students can explore these structural questions in more detail. For each molecule, structures obtained from PM3, HF(6-31G**), and DFT(B3LYP/6-31G**) calculations are included, as well as planar and non-planar structures of biphenyl. Measurement of the various bond and torsion angles using Jmol will help students develop a sense of the distance dependence of the non-bonded interactions and their importance in determining the actual structure. They might also wish to consider what additional degree(s) of freedom resveratrol and stilbene have that biphenyl does not, allowing the trans-form of the former molecules to remain planar under certain conditions, while minimizing the effect of the non-bonded repulsions.

Plant Chemistry |

Natural Products

Molecular Models of DAPIWilliam F. ColemanThis month's Featured Molecule is DAPI (4′,6-diamidino-2-phenylindole), from the paper by Eamonn F. Healy (1). The utility of DAPI is a consequence of its being a minor-groove binder to DNA. A crystal structure of DAPI binding to the minor groove of a synthetic DNA has been determined, and the structure file made available through the RCSB Protein Data Bank (2, 3). That structure is also included in the Featured Molecules Collection, with the water molecules removed for the sake of clarity. For many students this may be their first encounter with the binding of small molecules to DNA. Another example of such binding is the intercalation of the antibiotic actinomycin into DNA. The Department of Biology at the University of Hamburg maintains an excellent Web site showing both crystal and NMR structures of actinomycin intercalation (4). Observant students will also note in the structure of DAPI a theme that has appeared several times in our Featured Molecules, and that is the non-planarity of adjacent delocalized ring systems. In DAPI, it is a five-membered ring adjacent to a six-membered ring, and the observed departure from planarity is less than that in biphenyl. Students might be asked to explain that difference.

Nucleic Acids / DNA / RNA

Molecular Models of Rosmarinic Acid and DPPHWilliam F. ColemanThe paper by Canelas and da Costa (1) introduces students to the antioxidant rosmarinic acid, and its interaction with the free radical DPPH. Those two molecules are the featured species this month. The original paper shows the 2-dimensional structure of the cis isomer of rosmarinic acid, although the trans isomer exhibits very similar antioxidant properties. Calculations at the DFT/B3LYP 631-G(d) level show that the trans isomer is more stable than the cis isomer in the gas phase, a situation that is expected to carry over into solution. Many antioxidants are phenols, and rosmarinic acid has four such groups available for radical formation. A DFT study by Cao et al. (2) examines the relative stabilities of the radicals formed from loss of each of the phenolic hydrogens. That paper focuses on the trans isomer, and a useful student project would be to repeat the calculations with the cis isomer. An HPLC separation of the isomers of rosmarinic acid has been published (3), and might well lead to an extension of the experiment described in ref 1 in which relative antioxidant efficiencies of the two isomers could be evaluated. DPPH has been used extensively as a standard for determining antioxidant activity. An examination of the molecular orbital occupied by the lone electron shows significant delocalization, providing a partial explanation for the stability of the neutral radical. Our gas phase structure for DPPH, also at the DFT/B3LYP 631-G(d) level, is quite consistent with several crystal structures on DPPH and DPPH in the presence of another species (4).

Natural Products

Molecular Models of DyesWilliam F. ColemanThe paper on the synthesis of several dyes by James V. McCullagh and Kelly A. Daggett (1) provides us with the JCE Featured Molecules for this month. The authors mention various applications of these dyes, ranging from commercial dyeing to techniques for determining the course of complex biochemical processes. One of the reaction products, rhodamine B, is a member of a family of molecules that are widely used as tunable laser dyes. In this application, the rhodamines are most commonly encountered in a cationic form, rather than in the neutral form shown in the paper. In the cations, the carboxyl group is no longer part of a ring system. Several different members of the rhodamine family are included in the molecule collection because substituents have a marked effect on the effective lasing range of a given dye. Additionally, the solvent and the excitation source also influence the lasing range (2). Students can learn more about the relationship between structure, absorption and emission properties, and lasing ranges of various dyes by consulting ref 2 and from PhotochemCAD, Jonathan Lindsey's free application (3).

Dyes / Pigments

Collection of Chiral Drug, Pesticide, and Fragrance Molecular ModelsWilliam F. ColemanThe article by Mannschreck, Kiessewetter, and von Angerer on the differential interactions between enantiomers and biological receptors (1) is the source for this month's Featured Molecules. Included in the molecule collection are all of the molecules described in the paper. In many instances we have included structures of multiple optical isomers of the same molecule so that students can not only see the forms that are active, but those that are less active, inactive, or act in an undesirable manner. These molecules will serve as good practice in determining optical configurations, and will also introduce additional forms of isomerism that students may be less familiar with than they are with R and S. Since multiple enantiomers and diastereomers are provided, students may use these molecules, together with an appropriate computational package, to verify that enantiomers have the same energy while diastereomers do not. The tuberculosis drug ethambutol provides an interesting case as both nitrogen atoms are also chiral as well as the two chiral carbon atoms. A calculation on a given structure will include the effect of that nitrogen chirality, although nitrogen inversion is expected to be quite rapid in this molecule. The conformations for the ethambutol molecules that are included here consider all four chiral atoms and are of the form (CNNC). A reasonable computational exercise would be to find the transition state for nitrogen inversion and the barrier height for that process. The supplemental material that is included with the featured article (1) includes a number of molecules that we will add to the collection as time permits. The result, including enantiomers and diastereomers, will be well over 200 additional molecules. A notice will appear in the JCE Featured Molecules column when this new set of molecules is available in JCE Online.

Chirality / Optical Activity |

Biosignaling

Molecular Models of Real and Mock Illicit Drugs from a Forensic Chemistry ActivityWilliam F. ColemanThe Featured Molecules for this month come from the paper by Shawn Hasan, Deborah Bromfield-Lee, Maria T. Oliver-Hoyo, and Jose A. Cintron-Maldonado (1). The authors describe a forensic chemistry exercise in which model compounds are used to simulate the behavior of various drugs in a series of chemical tests. Structures of a number of the chemicals used in the experiment, and several of the drugs they are serving as proxy for, have been added to the molecule collection. Other substances used in the experiment are already part of the collection, including caffeine and aspirin. One structure that may be both intriguing and confusing to students is that of chlorpromazine (Thorazine, Figure 1). A majority of students might well expect the ring portion of the molecule to show a planar structure. This is not what is found from calculations at the HF/6311++G(d,p) level in both the gas phase and in water. Instead, the three rings are in a V-like formation with a deformation of approximately 50 degrees from planarity. Tracking down the source of this non-planarity would be a useful computational exercise. Does it arise from the presence of the alkyl chain (steric effect), from the chloro group (electronic effect), or from electronic effects involving the elements of the heterocyclic ring? As a starting point to addressing these questions, students could be introduced to the use of model compounds in computation. One such compound would be the parent ring system phenothiazine (Figure 2). That molecule contains neither a chloro substituent nor an extended alkyl group. Is it also found to be non-planar? Is the deformation angle the same, larger, or smaller than in chlorpromazine? Does the addition of chloro group to phenothiazene change the angle significantly? What about the addition of an alkyl group? If the model compound is forced to be planar are all of the vibrational frequencies real (positive)? If not, what type of deformation is suggested by the imaginary (negative) vibration?

Drugs / Pharmaceuticals |

Forensic Chemistry

Molecular Models of Reactants and Products from an Asymmetric Synthesis of a Chiral Carboxylic AcidWilliam F. ColemanOur JCE Featured Molecules for this month come from the paper by Thomas E. Smith, David P. Richardson, George A. Truran, Katherine Belecki, and Megumi Onishi (1). The authors describe the use of a chiral auxiliary, 4-benzyl-2-oxazolidinone, in the synthesis of a chiral carboxylic acid. The majority of the molecules used in the experiment, together with several of the pharmaceuticals mentioned in the paper, have been added to our molecule collection. In many instances multiple enantiomeric and diastereomeric forms of the molecules have been included. This experiment could easily be extended to incorporate various aspects of computation for use in an advanced organic or integrated laboratory. Here are some possible exercises using the R and S forms of the 4-benzyl-2-oxazolidinone as the authors point out that both forms are available commercially. Calculation of the optimized structures and energies of the enantiomers at the HF/631-G(d) level using Gaussian03 (2) produces the results shown in Table 1. Evaluation of the vibrational frequencies results in no imaginary frequencies and the 66 real frequencies are identical for the two forms. Examination of the computed IR spectra also shows them to be identical. Additionally, the Raman and NMR spectra can be calculated for the enantiomers and compared to experimental values and spectral patterns. A tool that is becoming increasingly important for assigning absolute configuration is vibrational circular dichroism (VCD). Although the vibrational spectra of an enantiomeric pair are identical, the VCD spectra show opposite signs, as shown in Figure 1. One can imagine a synthesis, using an unknown enantiomer of the chiral auxiliary, followed by calculations of the electronic and vibrational properties of all of the intermediates and the product, and determination of absolute configuration of reactants and products by comparison of experimental and computed VCD spectra. Using a viewer capable of displaying two molecules that can be moved independently, students could more easily visualize the origin of the enantiomeric preference in the reaction between the chelated enolate and allyl iodide.

Green Chemistry

Molecular Models of Products and Reactants from Suzuki and Heck SynthesesWilliam F. ColemanOur Featured Molecules this month come from the paper by Evangelos Aktoudianakis, Elton Chan, Amanda R. Edward, Isabel Jarosz, Vicki Lee, Leo Mui, Sonya S. Thatipamala, and Andrew P. Dicks (1), in which they describe the synthesis of 4-phenylphenol using an aqueous-based Suzuki reaction. The authors describe the various ways in which this reaction addresses concerns of green chemistry, and point out that their product bears structural similarity to two non-steroidal anti-inflammatory drugs (NSAIDs), felbinac and diflunisal. A number of molecules from this paper and its online supplemental material have been added to the Featured Molecules collection. Students will first notice that the aromatic rings in the molecules based on a biphenyl backbone are non-planar, as is the case in biphenyl. If they look carefully at diflunisal, they will notice that the carbon atoms are in a different chemical environment. One way in which to see the effect of these differing environments is to examine the effect of atom charge on the energies of the carbon 1s orbitals. Figure 1 shows this effect using charges and energies from an HF/631-G(d) calculation. A reasonable question to ask students would be to assign each of the data points to the appropriate carbon atom. As an extension of this exercise students could produce similar plots using different computational schemes. Are the results the same; are they parallel. This would be a useful problem when dealing with the tricky question of exactly what is meant by atom charge in electronic structure calculations. Students with more expertise in organic chemistry could explore extending the synthesis of 4-phenylphenol to produce more complex bi- and polyphenyl-based drugs. This may well be the first time that they have seen coupling reactions such as the Suzuki and Heck reactions. Students in introductory and non-science-major courses might well find the NSAIDs to be an interesting group of molecules, and could be asked to find information on the variety of molecules that display the anti-inflammatory properties associated with NSAIDs. Do they find structural similarities? Are there various classes of NSAIDs? Are they familiar with any of these molecules? Have they taken any NSAIDs? If so, for what reason? Is there any controversy about any of the NSAIDs? As with all of the molecules in the Featured Molecules collections, those added this month provide us with a number of ways of showing students the practical relevance of what they sometime see only as lines on a page. Molecules do matter.

Synthesis

Molecular Models of Antioxidants and RadicalsWilliam F. ColemanThis month's featured molecules come from the paper by John M. Berger, Roshniben J. Rana, Hira Javeed, Iqra Javeed, and Sandi L. Schulien (1) describing the use of DPPH to measure antioxidant activity. DPPH was one of the featured molecules in September 2007 (2) and the basics of antioxidant activity were introduced in last month's column (3). In addition, some of the other molecules in the paper are already in the featured molecules collection (4). The remaining structures in the Figure 1 and Table 1 of the paper have been added to the collection. All structures have been optimized at the 6-311G(D,P) level. These molecules suggest a number of possible student activities, some reminiscent of previous columns and some new. (R,R,R)-α-tocopherol is one of the molecules in the mixture that goes by the name vitamin E. These molecules differ in the substituents on the benzene ring and on whether or not there are alternating double bonds in the phytyl tail. In (R,R,R)-α-tocopherol the R's refer to the three chiral carbon atoms in tail while α refers to the substituents on the ring. (R,R,R)-α-Tocopherol is the form found in nature. An interesting literature problem would be to have students learn more about the vitamin E mixture and the differing antioxidant activity of the various constituents. Additionally they could be asked to explore the difference between the word natural as used by a chemist, and "natural" as used on vitamin E supplements. Can students find regulations governing the use of the term "natural"? Can they suggest alternative legislation, and defend their ideas? If students read about vitamin C they will discover that only L-ascorbic acid is useful in the body. It would be interesting to extend the experiment described in the Berger et al. paper (1) to include D-ascorbic acid. How do the antioxidant abilities of the enantiomers, as determined by reaction with DPPH compare? Is this consistent with the behavior in the body? Why or why not? Berger et al. mention two other stable neutral radicals, TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) and Fremy's salt. In a reversal from the use of stable radicals to measure antioxidant properties, these two molecules have proven to be very versatile oxidation catalysts in organic synthesis, and would make a rich source of research papers for students in undergraduate organic courses.

Free Radicals |

Natural Products

Molecular Models of Lycopene and Other CarotenoidsWilliam F. ColemanOver the past decade or so the phrase emerging research suggests has entered the argot of advertising, and that phrase has been applied to this month's Featured Molecule, lycopene, particularly with regard to potential health benefits of tomatoes. The paper by Jie Zhu, Mingjie Zhang, and Qingwei Liu (1) describes an extraction and purification of lycopene from tomato paste using an emulsion rather than the traditional solvent-based extraction. Lycopene is a member of the family of molecules called carotenoids, the most familiar of which is beta-carotene. This family of natural products includes more than 500 members that have been isolated and whose structures have been determined. Professor Hanspeter Pfander's research group at the University of Bern maintains a Web site with a significant amount of information on carotenoid structure, synthesis, and activity (2). Structurally one can think of carotenoids as consisting of three segments, a relatively rigid conjugated central portion with end groups. The end groups are, in general, flexible with respect to rotation about the bond connecting them to the central portion. For example, in beta-carotene, the dependence of total energy on the dihedral angle shown in Figure 1, displays a very broad range of essentially isoenergetic conformations (Figure 2). The energies shown in Figure 2 were calculated at the PM3 level using Hyperchem 7.5 (3). Calculations at the HF/631-G(d,p) level, with many fewer data points, show a similar trend. Many of the health benefits derived from various carotenoids are attributed to their antioxidant activities. Carotenoids react with singlet-oxygen in a physical, diffusion-controlled, quenching process that results in ground state triplet-oxygen and, following a non-radiative relaxation, ground state carotenoid. Of the various carotenoids that have been studied, lycopene and beta-carotene show the greatest quenching rate constants (4). The carotenoids provide us with countless explorations by students and teachers looking for connections between fundamental chemical concepts and real-world applications. Structure, reactivity, chemical synthesis, biosynthesis, and stereochemistry are just a few of the concepts involved in understanding the manifest important roles that these molecules play.

Plant Chemistry |

Natural Products

Molecular Models of Leaf ExtractsWilliam F. ColemanOur Featured Molecules this month come from the paper by Pelter et. al. on the analysis of leaf extracts by thin-layer chromatography (1). As the authors discuss, their experiment may be used in courses at various levels of the curriculum. The molecules discussed in the paper are also of wide interest both for their structural properties and their wide-ranging appearance in both natural and synthetic substances. Included in the molecule collection are all of the isomers for the molecules pictured in the text with the exception of menthyl acetate, for which only one structure is given (see below). All of these molecules have been optimized at the HF/631-G(d) level. The menthol family enantiomeric pairs of menthol, isomenthol, neomenthol and neoisomenthol provide a rich yet coherent group of molecules on which to base discussion of chirality, enantiomers and diastereomers. Treadwell and Black have described some of the differences in physical properties of four members of this family, and several other experiments using one or more menthols have been published in this Journal (2, 3). I have created a Web page in which the eight molecules are embedded in no particular order, and with no rational file names. This is being used in at least one of our organic sections to give students experience at identifying enantiomers, and diastereomers, and in applying R/S notation (4). As access to computational software becomes more common, and as efforts are being made to incorporate more relevant modeling experiments into all levels of the curriculum, the menthols again present some interesting possibilities. While students at the organic level know about enantiomers differing in their optical rotation, and about chiral molecules interacting with chiral and achiral environments, it is instructive for them to think of other ways in which enantiomers and diastereomers are the same or different. Three useful ways of checking to see whether two structures are truly enantiomers is to compute their total energies, vibrational spectra, and dipole moments. These calculations are available in most common computational packages. Figure 1 shows the results of energy calculations on optimized structures of the eight isomers. The enantiomeric pairs have, as expected, exactly the same total energy, while the various diastereomers differ in energy. The computation of the vibrational spectra is a very sensitive probe to determine whether two structures are optimized and enantiomeric or not. Structures that are almost enantiomeric, but not quite optimized, may exhibit similar energies, but the low frequency vibrations will be sensitive to any deviation from optimization. If two supposedly enantiomeric structures do not have the same computed vibrations, or if either shows a negative frequency, the structures need to be optimized more carefully. As with the vibrational frequencies, enantiomers should show identical dipole moments. Only one structure of the eight isomers in the menthyl acetate family is included in the collection, giving students the chance to build the other seven and verify their computed properties. Because of the central role that chirality plays in chemistry, and particularly in biochemistry, it seems appropriate to introduce some of these visualization and modeling exercises early in the curriculum, and in courses designed for students majoring in other areas. Students in various courses could pursue other aspects of these same molecules including odor and cooling properties, and green chemistry approaches to synthesizing menthols.

Plant Chemistry

Molecular Models of Annatto Seed ComponentsWilliam F. ColemanIn January 2008 the focus of this column was on the plant pigments lycopene and beta-carotene (1). Our attention this month returns to two papers discussing the pigments in annatto seeds (Figure 1), including direct precursors to lycopene. The paper by Teixeira, Durï¿½n, and Guterres describes the extraction and encapsulation of annatto seed components (2). The McCullagh and Ramos paper describes the separation of the pigment bixin from these seeds by TLC and column chromatography (3). These molecules could form the basis of interesting exercises across the chemistry curriculum. In courses designed for non-majors, students could choose a molecule from the table and search the literature for both scientific and non-scientific sources. Are the claims made in the latter sources regarding the health benefits of these molecules consistent with the scientific data? That discussion could be expanded to the more general question of how one tests the validity of statements made in what are essentially advertisements. Are any of these precursor molecules to lycopene considered to have anticancer properties (4)? In introductory or general chemistry courses, students could explore the various bond lengths and bond angles in the molecules to see whether they are consistent with their expectations based on simple bonding models. In introductory, organic, or biochemistry classes, the thermodynamics of hydrogenation and dehydrogenation could be examined. This might make an interesting alternative to the oft-discussed Haber Process. What conditions would one propose for a dehydrogenation process? Why are dehydrogenation reactions important? What enzymes catalyze the various dehydrogenation steps from phytoene to lycopene? These molecules could also be used in a variety of computational exercises in introductory and physical chemistry courses. Hartreeï¿½Fock calculations on a molecule such as phytoene may prove time-consuming depending on the nature of the computing system available. A good place to begin would be to perform semi-empirical calculations on the various molecules. Do the optimized structures match experimental results or the results of larger calculations? Does the HOMOï¿½LUMO gap correlate with the observed electronic absorption spectra? Which is more important in determining the difference in absorption between phytoene and phytofluene, the total number of double bonds or the number of bonds in the region of conjugation? Of course the aspect of these molecules that is most likely to capture student attention is their color, and they provide nice examples of the origin of color, the relationship between color observed and color absorbed, and, in upper level courses, the more detailed relationships of the energies of the ground and excited states.

Plant Chemistry |

Natural Products

Molecular Models of IndicatorsWilliam F. ColemanThe article by Nicholas C. Thomas and Stephen Faulk on "Colorful Chemical Fountains" (1) reminds us that color—the colors of acid–base indicators or of metal complexes—is responsible for many of us developing an interest in chemistry. The featured molecules this month are the acid and base forms of three common indicators–phenolphthalein, methyl orange, and methyl red. These three substances display interesting structural features as the pH-induced transformation from one form to another takes place in three different ways. In the case of phenolphthalein, the lactam ring is cleaved on deprotonation to produce a carboxyl group with the concomitant removal of a proton from a phenolic group. In methyl orange, one of the nitrogen atoms is protonated in the acid form, and that proton is lost in the base form. In methyl red, a carboxylic acid function is deprotonated. There are many other interesting aspects of acid–base indicators. Since most plants and fruits contain pigments that show a color change in some pH range, it is difficult to state with any degree of certainty when these changes were first put to use in a systematic fashion. The Spanish alchemist Arnaldus de Villa Nova (Arnold of Villanova) is purported to have used litmus in the early 14th century. In general systematic use of indicators is traced to the latter half of the nineteenth century with the development of the three synthetic indicators described above. Many students will be familiar with the use of phenolphthalein to identify blood—often shown on the various forensic chemistry TV dramas by dropping some solution on a cotton swab that has been used to pick up some of the sample in question. If the swab turns red we frequently hear "It's blood". The reality of using phenolphthalein in this way is more complicated. The test is presumptive for the presence of blood, but not conclusive. It is not an acid–base reaction but rather, in the presence of hydrogen peroxide, relies on hemoglobin to catalyze the oxidation of phenolphthalein. An interesting assignment for students in a high-school or non-majors course would be to have them explore the details of this Kastle–Meyers test to see just what is involved in the correct application of the test, and what factors complicate the process. For example, would tomato juice infused with asparagus juice give a positive Kastle–Meyers test? Historically phenolphthalein was used in a variety of laxatives. Recently that usage has been discontinued due to concern about the carcinogenic nature of the substance. A review of the history of the controversy surrounding the use of phenolphthalein in laxatives would make a good research paper at the high-school level. Lastly, students with some practice building structures and performing calculations might wish to explore the structures of two other forms of phenolphthalein—one found in very acidic solutions, having an orange color, and one found in very basic solutions that is colorless.

Molecular Properties / Structure

Molecular Models of Peroxides and AlbendazolesWilliam F. ColemanThis month our featured molecules come from two sources, the paper by Marina Canepa Kittredge, Kevin W. Kittredge, Melissa S. Sokol, Arlyne M. Sarquis, and Laura M. Sennet on the stability of benzoyl peroxide (1) and the paper by Graciela Mahler, Danilo Davyt, Sandra Gordon, Marcelo Incerti, Ivana NÃºÃ±ez, Horacio Pezaroglo, Laura Scarone, Gloria Serra, Mauricio Silvera, and Eduardo Manta on the synthesis of an albendazole metabolite (2).The benzoyl peroxide paper is targeted at non-majors courses, but the molecule and related peroxides contain a number of interesting structural features that could be explored in traditional introductory and in upper-level courses. The first feature is the OO bond itself. In the three examples included in the collection the bond length computed at the B3LYP/6-311++G(d,p) level ranges from 133.8 pm for dimethyl peroxide to 144.9 pm for hydrogen peroxide. The experimental value for the latter is 147.5 pm and the Computational Chemistry Comparison and Benchmark DataBase (CCCBD) gives a wide range of computed OO bond lengths in H2O2 for more than 20 model chemistries (3).The XOOXʹ dihedral angle in these peroxides also shows interesting properties that have been difficult to reproduce theoretically. In hydrogen peroxide the experimental value is 119.8Â°, while our calculation gives 121.5Â°. Again the CCCBD reports a wide variation in this angle, including methods that produce a value of 180Â°. On the other hand, our model of benzoyl peroxide has a dihedral angle of 86.6Â°, and dimethyl peroxide shows a dihedral angle of 180Â°. Weinhold and Landis discuss the angle in hydrogen peroxide in terms of a stabilization of the gauche form through an nσ* interaction between oxygen lone pairs and empty CO σ* orbitals (4). Many levels of theory produce 180Â° dihedral angles for dimethyl peroxide and, as Tonmunphean, Parasuk, and Karpfen have pointed out, minima in the 120Â° range are not observed until coupled-cluster models are applied (5). The accepted experimental structure with a 119 Â± 10Â° dihedral angle comes from an electron diffraction study (6). These experimental and high-level theoretical calculations lead us to conclude that the model proposed by Weinhold and Landis applies to more complex peroxides as well as to H2O2.In the case of albendazole and the oxygenated albendazoles, it is interesting to monitor the computed charges on the sulfur atoms with oxygenation. The charges on the sulfur atoms, computed at the B3LYP/6-311++G(d,p) level, are 0.066, 0.768 and 1.123 for 0, 1 and 2 oxygens on the sulfur atom respectively. Students could be asked to predict and explain the order of the charges, and to comment on how the charges inform the description of bonding about the sulfur atom. To what extent is the hypervalent species ionic? Does this influence how we should think of d-orbital participation in such molecules?

Molecular Modeling

Shapes of d OrbitalsWilliam F. ColemanShapes of d Orbitals shows the d orbitals in an axis set. Running the mouse over an orbital reveals the "name" of that orbital. This is good practice for helping students link the name of an orbital to the orientation.Shapes of d Orbitals has a link to D Orbitals in an Octahedral Ligand Field. Here the user may click on the name of any one of the d orbitals to obtain a larger 3-dimensional image. The images are rotatable and scalable. Orbital phase is shown by the different colors.

Enrichment / Review Materials |

Atomic Properties / Structure |

Crystal Field / Ligand Field Theory

Featured Molecule Sample Web PageWilliam F. Coleman, Randall J. WildmanOver the next few months we will be announcing some new and exciting additions to the scope of JCE WebWare, our online feature that publishes Web-based materials for chemical education. One such addition is providing interactive images available at the JCE WebWare site that are linked to molecular structures or other graphic images of articles printed in this Journal. As an example, a significant fraction of articles in the Journal of Chemical Education include one or more molecular structures naturally in a two-dimensional representation. We would like to build a collection of interactive Chime-based structures for some of these molecules. While many such structures exist in other Web-based collections, having them in one location and linked to a specific article in JCE will greatly benefit both teachers and students. Below is an example of such a collection, derived from a paper in C & E News. Many students have difficulty "seeing" molecules in three dimensions and linking two-dimensional with three-dimensional representations of molecular structures. The more they practice doing so, the more skilled they will become. Additionally, as we try to teach students to draw "form/function" conclusions about molecular behavior, "seeing" the three-dimensional structure is crucial.

Molecular Modeling

Organic XenobioticsWilliam F. ColemanThe molecules for this month come from the article, Intermolecular Forces as a Key to Understanding the Environmental Fate of Organic Xenobiotics, by Ryan E. Casey and Faith A. Pittman. The paper describes an interesting approach to introducing students in an environmental science course, with no required chemistry background, to important questions of the ways in which molecular geometry and polarity affect the behavior of organic molecules in the environment.

Titration (ChemPages Lab)John W. Moore, Jerrold J. Jacobsen, Joe L. MarchTitration: this is a resource in the collection "ChemPages Laboratory Resources". A titration is a laboratory procedure for quantitative analysis. Titrametric analysis is used to determine the concentration of an analyte in solution, the stoichiometry of a reaction, the number of electrons gained or accepted in a redox reaction and the solubility products. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

Laboratory Equipment / Apparatus

Electrostatics Attraction (GCMP)David M. WhisnantElectrostatics Attraction: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will correlate molecular polarity with the attraction of liquids to a charged rod. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Noncovalent Interactions

The Relation of Temperature to Energy SpreadsheetChristopher KingThe relation between temperature, energy, and the properties of a material is well developed. While this relation is not clearly elaborated in most physical chemistry textbooks, these relationships can easily be included in the early part of a physical chemistry course on thermodynamics, and this interactive Excel spreadsheet can help.

Theoretical Chemistry |

Thermodynamics

Flying Over AtomsJohn R. MarkhamFlying Over Atoms provides tools for teaching about atoms and solid surfaces in an introductory chemistry course. Flying Over Atoms introduces and stimulates interest in atomic surfaces and current methods for imaging at the atomic scale. Flying over Atoms uses Scanning Tunneling Microscope (STM) data and the software program Vistapro, published by Rom Tech, Inc. (not provided) to allow students to create QuickTime movies of atomic landscapes.

Lake StudyDavid M. Whisnant, James A McCormick, Benjamin Fortin, Patrick NutterLake Study for Windows is a two-part simulation designed to involve students with the scientific method. It allows them to collect data, formulate hypotheses, and test the hypotheses with controlled experiments.

How Accurate Is the Steady State ApproximationLars Ole Haustedt, Jonathan M. GoodmanThe steady-state approximation is commonly used in enzyme catalysis kinetics calculations, but how much error does the approximation introduce? This Java applet allows you to visually determine the accuracy of the steady-state and pre-equilibrium approximations.

Equilibrium

Universal Algorithm for Acid-Base Equilibrium CalculationsPavol TarapèíkThese Microsoft Excel workbooks facilitate the calculation of the equilibrium composition of simple to complex acid-base systems. Three workbooks are available: 1. pH-mix calculates the equilibrium composition for any mixture of protolytes. 2. pH-titr calculates and presents titration curves. 3. pH-titrd calculates and presents titration curves with derivative curves included. The workbooks require only basic knowledge about Excel and almost no calculation abilities. However, they do require a description of chemical properties of the system components. Thus they allow students to concentrate on chemistry skills rather than laborious algebra and arithmetic.

Acids / Bases

Principles of Gel Permeation ChromatographyGuilherme Andrade Marson, Bayardo Baptista TorresPrinciples of Gel Permeation Chromatography presents the principles of gel permeation chromatography (GPC) for students in introductory undergraduate courses of chemistry and biochemistry. These principles are presented in four sections: Introduction, Real Lab, Virtual Lab, and Microscopic Model. The Introduction and Real Lab sections present a brief view of the basic experimental apparatus typically used in laboratory GPC in order to provide a concrete connection of the real process of separation. The basic elements of column chromatography, emphasizing the stationary and mobile phases, are presented in the Introduction, followed by a sequence of pictures and texts describing major steps in GPC analysis in the Real Lab section. The Virtual Lab section is a simulator. Three samples are available for a virtual GPC experiment: sample 1, containing hemoglobin; sample 2, containing methylene blue; and sample 3, containing both methylene blue and hemoglobin. Each sample undergoes a virtual separation run, which is dynamically represented in three ways in the software: a virtual column, the collected fractions, and a virtual chromatogram. This threefold representation allows the simultaneous view of key aspects of the process to demonstrate the correlation between the experimental procedure and the resulting chromatogram.

Chromatography

A Lattice Energy SpreadsheetChristopher KingA Lattice Energy Spreadsheet is a tool that easily calculates lattice energies. It also illustrates the relation between crystal structure, coordination number, and ionic radii. A Lattice Energy Spreadsheet contains five related worksheets: Lattice Energy, MX Structure Map, Kapustinsky Lattice Energy, Directions, and Discussion, each described below. In the Lattice Energy worksheet, the lattice energy of many binary compounds can be calculated in about a dozen mouse clicks. An element is selected, and the radius corresponding to the desired charge and coordination number is selected. The same is done for the counter ion, and the anticipated crystal structure of the compound is chosen (rock salt, wurtzite, etc.). The lattice energy is then calculated. This sheet uses enthalpies of formation of monatomic gaseous atoms from the elements, ΔH°form, to calculate lattice energies. The results are more accurate than the values obtained by simply summing enthalpies of fusion and vaporization. The results of the corresponding Born-Haber cycle are also graphed on this sheet.

Thermodynamics

Self-Consistent Field Calculations SpreadsheetGary G. HoffmanA Self-Consistent Field Calculations Spreadsheet can help your students understand the self-consistent field (SCF) procedure, typically presented in an undergraduate physical chemistry course. The spreadsheet helps students easily perform SCF calculations on a two-electron atom and see graphically how the proper solution is obtained. It is also possible for more advanced students to apply this spreadsheet to more ambitious systems. The wave function for the two-electron atom is assumed to be a product of two identical one-electron orbital functions. The system is assumed to be a spin-singlet so that only the spatial functions need to be considered here. The SCF procedure involves two repeated steps. First, using a guess for the orbital function, an effective potential is generated. Second, with this effective potential, the differential equation for the orbital function is solved. The new orbital function is used to generate a new effective potential, which is then used to generate a newer orbital function. The procedure is repeated until successive orbital functions are considered to be close enough to each other. A Self-Consistent Field Calculations Spreadsheet file contains two spreadsheets. The first is the one described in the associated article (1). It performs the calculation with relatively simple approximations and numerical methods, and serves to illustrate the SCF procedure for the student. The second presents a more sophisticated calculation that may be of interest to more advanced students.

A Pedagogical Simulation of Maxwell's Demon ParadoxD. López, C. CriadoMaxwell's demon was conceived by James Clerk Maxwell in 1871 to illustrate the statistical basis of thermodynamics (1), and the concept has since formed an arena for investigation and clarification of many concepts in thermodynamics (2). Chemistry students often have difficulty developing an intuitive knowledge of some concepts in thermodynamics. A Pedagogical Simulation of Maxwell's Demon aims to help make these concepts more understandable for students. Teaching thermodynamics from the microscopic point of view can help students develop an intuitive understanding of its concepts. This program simulates, at the microscopic level, two gas chambers with an opening between them. The program allows students or their instructors to set up simulations that illustrate the thermodynamics and statistical behavior of the system. The user determines the basis for whether the demon permits or denies passage of particles through the opening using information from the microscopic level, such as specific particle velocity. Students can track and analyze how this affects particle distribution, thermal equilibrium, relaxation time, diffusion, and distribution of particle velocities.

Thermodynamics

Things We UseVolume 03, issue 01 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Metallurgy |

Consumer Chemistry |

Industrial Chemistry

Water and Its ElementsVolume 03, issue 02 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Water / Water Chemistry |

Geochemistry

Families of ElementsVolume 03, issue 03 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Atomic Properties / Structure |

Descriptive Chemistry

The Chlorine FamilyVolume 03, issue 04 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Industrial Chemistry |

Consumer Chemistry |

Medicinal Chemistry

Chemicals Used in IndustryVolume 03, issue 05 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Industrial Chemistry |

Agricultural Chemistry

The Sulfur FamilyVolume 03, issue 06 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Geochemistry |

Industrial Chemistry

NitrogenVolume 03, issue 07 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Industrial Chemistry |

Agricultural Chemistry

Importance of AirVolume 03, issue 08 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Atmospheric Chemistry

The World's Food SupplyVolume 03, issue 09 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Plant Chemistry |

Photosynthesis |

Proteins / Peptides |

Carbohydrates |

Lipids |

Nutrition

Aviation-Lighter-than-air CraftVolume 03, issue 10 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Industrial Chemistry |

Gases

The Phosphorous FamilyVolume 03, issue 11 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Industrial Chemistry |

Descriptive Chemistry

CarbonVolume 03, issue 12 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Agricultural Chemistry |

Geochemistry

Carbon CompoundsVolume 03, issue 13 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Bioorganic Chemistry |

Alkanes / Cycloalkanes

Coal and Its By-ProductsVolume 03, issue 14 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Geochemistry |

Industrial Chemistry

The World's Clothing SupplyVolume 03, issue 15 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Consumer Chemistry |

Plant Chemistry

Synthetic ProductsVolume 03, issue 16 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Materials Science |

Consumer Chemistry

The Silicon FamilyVolume 03, issue 17 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Metalloids / Semimetals |

Materials Science

How the World Is HousedVolume 03, issue 18 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Consumer Chemistry |

Industrial Chemistry

The Boron FamilyVolume 03, issue 19 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Descriptive Chemistry

The Sodium FamilyVolume 03, issue 20 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Descriptive Chemistry

The Calcium FamilyVolume 03, issue 21 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Descriptive Chemistry

The Zinc FamilyVolume 03, issue 22 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Descriptive Chemistry |

Plant Chemistry

Aviation-Heavier-than-air CraftVolume 03, issue 23 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Materials Science |

Industrial Chemistry

Precious MetalsVolume 03, issue 24 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Geochemistry |

Metallurgy

Copper, Brass, BronzeVolume 03, issue 25 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Metallurgy

Tin and LeadVolume 03, issue 26 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Metallurgy |

Dyes / Pigments

Iron and SteelVolume 03, issue 27 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Metallurgy

NickelVolume 03, issue 28 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Metallurgy

Chromium and Its RelativesVolume 03, issue 29 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Dyes / Pigments |

Metallurgy

Vanadium and Its RelativesVolume 03, issue 30 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Metallurgy

Modern Atomic TheoryVolume 03, issue 31 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Atomic Properties / Structure

Elements That DisintegrateVolume 03, issue 32 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Nuclear / Radiochemistry |

Medicinal Chemistry

LightsVolume 03, issue 33 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.

Consumer Chemistry |

Industrial Chemistry

Unusual ElementsVolume 03, issue 34 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.